Quick answer: Repair almost always wins financially when the fault is a single component — a screen, battery, or charging port — on a phone you plan to keep for at least another year. Replacement starts to make more sense when you're facing multiple faults at once, the phone is already several generations old, or the repair cost approaches what a good used replacement of the same model would cost. The worked examples and formula below let you run the numbers on your own phone in a couple of minutes.
A note on how to use this guide: we're not going to pretend a single generic rule ("replace if repair costs more than 50% of the phone's value") works for every situation, because it doesn't — a battery replacement and a motherboard failure carry completely different risk profiles even at the same price point. Instead, this is a step-by-step method plus worked examples, so you can apply it to your own phone and fault.
The four numbers you need before deciding anything
- Current used resale value of your phone, in its current condition. Check completed listings on a marketplace for your exact model, storage size, and condition — not the original retail price.
- The cost of the part(s) you need. Check real pricing for your specific model rather than assuming — costs vary hugely by generation and part type.
- Labour cost, if you're not doing it yourself. Get an actual quote rather than guessing; repair shop pricing varies significantly by region and by fault complexity.
- How long you plan to keep the phone. A repair on a phone you'll replace in three months is a different calculation to a repair on a phone you plan to use for two more years.
The formula
Once you have those four numbers, the decision comes down to comparing two totals:
Repair cost = part cost + labour cost (£0 if DIY)
Replacement cost = price of a comparable used/refurbished phone − your phone's current resale value in faulty condition
If repair cost is meaningfully lower than replacement cost, and you're not facing multiple simultaneous faults, repair is very likely the better financial decision. If they're close, or replacement is actually cheaper, the ownership-length question becomes the deciding factor — a phone you'll keep for two more years justifies a repair even at a higher relative cost than one you were already planning to replace soon.
Worked example 1: iPhone 14, cracked screen only
| Factor | Value |
|---|---|
| Phone's resale value with a cracked screen | Roughly 40-50% below working-condition resale value |
| Replacement LCD screen part cost | From £18.99 (iPhone 14 FHD LCD screen) |
| Typical professional fitting labour (UK) | Varies by shop — get a local quote |
| Cost of a comparable used iPhone 14 in good condition | Significantly more than the repair cost in almost every case |
Verdict: repair. A single cracked screen on an otherwise-working iPhone 14 is one of the clearest "repair wins" scenarios — the part cost is low, the fault is isolated, and the resale value gap between "cracked screen" and "working" condition is large enough that fixing it before selling (or before continuing to use it) almost always pays for itself.
Worked example 2: Samsung Galaxy S24, battery only
| Factor | Value |
|---|---|
| Symptom | Battery health degraded — shuts down early, drains fast |
| Replacement battery part cost | From £10.34 (Samsung Galaxy S24 replacement battery) |
| Everything else on the phone | Working normally |
Verdict: repair, almost without exception. A degraded battery on an otherwise fully-functional flagship phone is the single best-value repair category that exists — low part cost, straightforward fitting, and it resolves the single most common reason people consider replacing a phone that's otherwise perfectly good.
Worked example 3: older phone, screen and battery and charging port all faulty
| Factor | Value |
|---|---|
| Phone age | 4+ generations old |
| Faults | Screen, battery, and charging port all need replacing |
| Combined part cost | Adds up across three separate repairs, plus labour for each if not DIY |
| Resale value even after repair | Low, due to phone age |
Verdict: this is where it gets genuinely close, and depends on your ownership plans. Three simultaneous faults on an older phone is the scenario where combined repair costs can approach or exceed what a good used replacement of a newer model would cost. If you plan to keep using this exact phone for years to come and have an emotional or practical reason to (familiar setup, specific storage needs, a phone that otherwise still works well for you), repairing all three is still often reasonable — labour and parts remain cheaper than a new device in absolute terms. If you were going to upgrade soon anyway, this is the point where replacement starts to make more financial sense.
When repair is (almost) always right
- A single, isolated fault — one screen, one battery, one charging port
- The phone is otherwise in good working order
- You plan to keep using the phone for a year or more
- The part cost is a small fraction of the phone's working resale value
When replacement deserves serious consideration
- Multiple simultaneous faults, especially if one involves motherboard-level damage
- The phone is already several generations behind current models and losing software update support soon
- Combined repair cost approaches the price of a good used or refurbished newer model
- You were already planning to upgrade within the next few months regardless of the fault
Why we're not giving you a live calculator tool (and what to use instead)
You'll see "repair or replace" articles elsewhere promising an interactive calculator. Building one properly — with live resale-value lookups and accurate regional labour pricing — is a genuine software project, not something that belongs bolted onto a blog post as a gimmick. Rather than ship something inaccurate, this guide gives you the real formula and three fully worked examples covering the most common scenarios, so you can plug in your own numbers directly. If you want a precise answer for your specific phone and fault, browse the exact part cost for your model and compare it against a genuine, current resale listing for your phone in its present condition — that two-minute check is more accurate than any generic calculator could be anyway, since resale values shift constantly.
The risk-profile difference between repair types
Not all repairs carry the same risk if something goes wrong, and that's worth factoring in separately from pure cost:
- Screen and battery replacements are low-risk, well-understood repairs with a high success rate, even for confident DIYers. If a mistake happens, the failure mode is usually obvious (screen doesn't light up, battery doesn't charge) rather than silent.
- Charging port replacements sit in the same low-to-moderate risk category, though on some models they're combined with microphone or other components, so a mistake can affect more than just charging.
- Motherboard-level repairs (liquid damage, drop damage affecting internal components) carry meaningfully higher risk and are the category where "just try it yourself" advice is least appropriate — a failed attempt can turn a repairable fault into an unrepairable one.
Factor this into your decision alongside pure cost: a cheap part attached to a high-risk repair isn't automatically the better choice over a slightly more expensive but lower-risk path.
Hidden costs people forget on both sides of the comparison
The headline numbers rarely tell the whole story. A few things worth factoring in before you commit either way:
- Data transfer time. Replacing a phone means setting up a new device — restoring apps, re-authenticating accounts, re-pairing accessories. This isn't a cash cost, but it's real time, and it's zero if you repair.
- Accessory compatibility. Cases, screen protectors, and docks bought for your current phone may not fit a replacement, especially if you switch model generations or brands. This can add £20-£50 to the effective cost of replacing.
- Warranty on the repair itself. Check whether the part or the fitting comes with any warranty — a repair with a reasonable warranty period reduces the risk of the "what if it fails again" scenario that sometimes pushes people toward replacement out of caution rather than cost logic.
- Environmental and disposal considerations. Repairing keeps a working device in use for longer, which some buyers factor into their decision beyond pure cost — not something we'll put a number on, but worth naming since it's a real factor for a growing number of people.
- Depreciation on the replacement. A "new" replacement phone starts depreciating the moment you own it too — the comparison isn't repair-cost-once versus replacement-cost-once, it's repair-cost-once versus replacement-cost-plus-ongoing-depreciation-on-a-different-asset.
Step-by-step: running the numbers on your own phone
- Look up your phone's current resale value in its faulty condition, and separately in working condition, using recent completed marketplace listings for your exact model and storage size.
- Check the real part cost for your specific fault and model — don't estimate, check the actual listing.
- Get a labour quote if you're not doing it yourself, or confirm you have the tools and confidence to DIY.
- Add part cost and labour together for your total repair cost.
- Subtract your phone's faulty-condition resale value from the cost of a comparable used replacement to get your true replacement cost (not just the sticker price of a new phone).
- Compare the two totals, then weigh in how long you plan to keep the phone and how many separate faults you're dealing with.
Frequently asked questions
Is it ever worth replacing a phone over a single fault?
Rarely, if the fault is isolated and the phone is otherwise in good condition. The exception is when you were already planning to upgrade imminently regardless of the fault — in that case, the repair cost is effectively wasted money on a device you're about to stop using anyway.
Does phone age alone make repair not worth it?
Age matters less than most people assume, provided the phone still receives software updates and the fault is isolated. A five-year-old phone with a cracked screen and nothing else wrong is still usually cheaper and more sensible to repair than replace, as long as you're happy continuing to use that generation of device.
What's the biggest mistake people make in this decision?
Comparing repair cost against the price of a brand-new phone, rather than against a realistic used or refurbished replacement of similar age and specification. That comparison almost always makes replacement look artificially better than it actually is.
Should I repair a phone I'm about to sell?
Usually yes, if the repair cost is meaningfully lower than the resale value gap between faulty and working condition — which is very often true for screens and batteries specifically. Get the resale figures for both conditions before deciding, rather than assuming.
Is DIY repair worth it to save on labour costs?
For screens, batteries, and charging ports, DIY is a reasonable option if you're reasonably confident with small tools and follow a proper guide — it removes labour cost entirely and these are well-documented, lower-risk repairs. For anything involving liquid damage or motherboard-level faults, professional diagnosis is usually worth the labour cost given the higher risk of turning a fixable problem into an unfixable one.
How much does labour typically add to a repair?
This varies significantly by region, shop, and fault complexity, so always get a specific quote rather than assuming a figure. As a general pattern, screen and battery labour tends to sit at the lower end of repair labour pricing since these are high-volume, well-practised jobs for most shops, while diagnostic-heavy repairs (intermittent faults, suspected motherboard issues) tend to cost more in labour because they require investigation time before the actual fix begins.
Summary
Repair a single isolated fault on a phone you plan to keep — that's the clearest, most common scenario and it almost always favours repair. Replacement earns serious consideration only when you're facing multiple simultaneous faults, the phone is already near the end of its useful life, or you were planning to upgrade regardless. Run the actual numbers for your specific phone and fault rather than relying on a generic rule of thumb — the formula and worked examples above will get you a genuinely accurate answer in a couple of minutes.