By Alex Chen — PC Hardware Reviewer with 8+ years in field repair. About this site.

Your computer is slow, broken, or just feels old. The repair shop quoted you a number that sounds about half what a new laptop costs. Now what?

Most people answer this question with vibes. They either get attached to the machine they have and overspend repairing it, or they panic and replace a computer that needed a $60 part. This guide gives you a real framework, used by professional repair techs, to make the call in about ten minutes.

What’s in this guide

  1. The 50% cost test (the only rule that matters)
  2. The age test — when a machine is past its useful life
  3. The symptom-by-symptom decision matrix
  4. 5 real-world scenarios with verdicts
  5. The hidden costs of replacing
  6. FAQ

Step 1: The 50% Cost Test

This is the single most useful rule in computer repair: if the proposed repair costs more than 50% of a comparable new machine, replace.

The reason is simple. A new laptop comes with a fresh battery, a fresh warranty, and parts that are years away from their next failure. A repaired old laptop has the rest of its components ticking down. Spending $400 to fix a $700 machine that’s already six years old is the textbook bad deal.

Examples of the 50% test in action

Important: “Comparable new” means the same general performance tier, not whatever the salesperson is upselling. A 5-year-old i5 laptop is comparable to a $400–$600 new machine, not a $1,200 ultrabook.

Step 2: The Age Test

Even if a single repair passes the 50% test, age changes the math. The older the machine, the more likely the next thing will fail next month.

Age Laptop Desktop
0–3 years Always repair — still under or near warranty Always repair
3–5 years Repair if under 50% rule Repair — desktops have years left
5–7 years Depends — only repair if you also upgrade the SSD/RAM Usually repair
7–10 years Replace — battery and other parts will fail anyway Depends — desktops can keep going with upgrades
10+ years Replace Usually replace unless it’s a beloved gaming rig you’re still upgrading

Step 3: The Symptom-by-Symptom Matrix

Different problems have wildly different verdicts. Find your symptom in the table below.

Symptom Verdict Typical fix
Slow boot, slow programs Repair SSD upgrade ($60–100) + clean install. See our SSD picks.
Runs out of memory, multitasking is painful Repair RAM upgrade ($30–80) if upgradable
Loud fans, overheating, throttling Repair Clean dust + replace thermal paste ($0–30 DIY)
Battery only lasts 30 minutes Repair if under 5 years old Replacement battery ($40–120). After 5+ years, weigh against age test.
Cracked screen, otherwise healthy Repair Screen replacement ($80–200 parts + labor)
Keyboard keys not working Repair Keyboard replacement ($30–120) or external USB keyboard
Failing hard drive, blue screens Repair Replace with SSD + reinstall Windows ($60–100)
Suspected virus or ransomware Repair Clean Windows install ($0). See our virus guide.
Liquid spill, won’t turn on Depends Get a free diagnostic. If motherboard is dead, replace.
Motherboard failure Replace Motherboard repair on a 4+ year old laptop is rarely worth it
CPU failure (rare) Replace CPU and motherboard usually need to be replaced together
Multiple failures (screen + battery + slow) Replace Total repair cost almost always exceeds the 50% test

Step 4: 5 Real Scenarios With Verdicts

Repair

1. The college student’s 4-year-old laptop is unbearably slow

$60 SSD + $40 RAM + a free clean Windows install will turn it into a different machine. We see this every week. The repair pays for itself in two weeks of not waiting on it. Read the speed-up guide first — some of the wins are free.

Repair

2. Your 3-year-old gaming PC is making a buzzing noise

It’s a fan. Or a failing power supply. Either is $30–80 to replace, well under the 50% test, and the rest of the machine has years left. A desktop PSU swap is a 20-minute job.

Depends

3. The 6-year-old laptop with a cracked screen and slow boot

The cracked screen alone passes the 50% test. The slow boot alone passes too. Together it’s closer: $180 screen + $80 SSD + $50 labor = $310 against a $500 replacement. Borderline. Lean repair if the chassis and battery are still good. Lean replace if you’ve also been thinking the keyboard feels mushy.

Replace

4. The 7-year-old laptop’s motherboard died

$280 motherboard repair on a machine worth $250 used. The 50% test failed in spectacular fashion. The age test failed too. Buy a refurbished or new entry-level laptop — see our budget laptop picks under $500.

Replace

5. The 10-year-old desktop “just needs a few things”

The original power supply is on borrowed time, the motherboard is two CPU sockets out of date so a CPU upgrade requires a motherboard which requires new RAM which requires a new graphics card… you’re building a new computer one part at a time and paying more for the privilege. Cut your losses.

The Hidden Costs of Replacing

Replacing isn’t just the price of the new computer. Before you write that off the math, factor in:

For a smooth transition, our PC Maintenance Guide includes a complete migration checklist so you don’t lose a tab, a license, or a saved game.

So Which Should You Do?

Run the four steps in order:

  1. Apply the 50% cost test — if the repair is more than half the price of a comparable new machine, lean replace.
  2. Apply the age test — older machines tilt the verdict toward replace even on a passing cost test.
  3. Look up your specific symptom in the matrix — some problems are always cheap, some are always terminal.
  4. Sanity-check against the scenarios — if your situation looks like a replace scenario, it probably is.

If the verdict is repair: read our speed-up guide for the free fixes first, then our SSD upgrade guide for the single biggest paid upgrade you can make.

If the verdict is replace: see our best budget laptops under $500 for the no-overspending pick.

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Frequently Asked Questions

How much should I spend repairing an old computer?

If the repair cost exceeds 50% of the price of a comparable new computer, replace. For a 5-year-old laptop, a comparable new one usually costs $400–700, so any single repair north of $250 is hard to justify.

Is a slow computer worth repairing?

Almost always. Slowness is usually fixed by an SSD upgrade ($60–100), a RAM upgrade ($30–80), or a clean Windows reinstall (free). Together they often deliver an 80–90% performance lift for under $150 — cheaper than a tank of gas.

When should I just buy a new computer?

Replace if the motherboard or CPU has failed, the laptop has physical damage to both screen and chassis, the machine is more than 7 years old and needs more than one repair, or you’ve already replaced the storage and RAM and it’s still too slow for your workload.

How long should a laptop last?

A well-maintained laptop should last 5–7 years for everyday use. With an SSD upgrade and a fresh OS install partway through, many push to 8–10 years. Desktops typically last 7–10 years before becoming uneconomical to upgrade.

Is it worth fixing a cracked laptop screen?

Sometimes. Screen replacements run $80–200 in parts plus 30–60 minutes of labor. If the laptop is otherwise healthy and under 4 years old, fix it. If it’s older and slow on top of being cracked, the math usually favors replacing the whole machine.

Is buying a refurbished computer a good middle ground?

Yes — manufacturer-refurbished machines (Dell Outlet, Lenovo Outlet, Apple Refurbished) come with full warranty and run 20–40% off new. They’re a strong option when your old machine has failed but you don’t want to spend new-machine money.

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