Run them too long and you pay in lost productivity and support time. Replace too early and you waste capital. Here is the sweet spot, with the numbers behind it.
The three-to-four year rule
For most office laptops, three to four years is the economic sweet spot, and it lines up with how long manufacturers warrant business hardware. Past the four-year mark, battery capacity has typically fallen below 70% of new, mechanical and thermal faults climb, and the operating system starts ageing out of support. The machine still switches on — it just quietly costs you more every month than it would to replace.
The cost nobody puts on a spreadsheet
Here is the maths that changes minds. If a slow, ageing laptop costs a staff member just 10 minutes a day in waiting — boot times, spinning beachballs, crashes — that is roughly 40 hours a year. On an average salary, those lost hours are worth far more than a new mid-range laptop. The replacement is not a cost; it is usually a saving the moment you account for time.
The warning signs
Watch for boot times over a minute, fans running constantly, storage permanently full, frequent crashes, or a device that can no longer install OS updates. Any two of these together is the signal. A surprising number can be bought another year cheaply with an SSD and RAM upgrade — but past four years, replacement is almost always the better call.
Security ages too
This is the part owners underestimate. When a laptop falls out of vendor support, it stops receiving security patches, and an unpatched machine on your network is a doorway for everyone else. The ACSC lists patching and supported operating systems among its Essential Eight controls for exactly this reason. An old laptop is not just slow; it is a liability.
Make it boring and predictable
The smartest businesses never face a big replacement bill. They run a rolling three-year cycle, refreshing a third of the fleet each year, so it becomes a planned, budgeted line item instead of a crisis. At Elevate we track device age and warranty across managed clients and flag machines before they become a problem — so the decision is always made calmly, never at 4pm on a deadline.
Old kit is an environmental and security cost too
There is a sustainability angle worth naming. E-waste is the fastest-growing waste stream in the world, with the UN estimating over 60 million tonnes generated globally each year, and only a fraction properly recycled. Replacing thoughtfully — and disposing of the old device responsibly — matters. So does the data on it: a laptop retired without certified data destruction is a breach waiting to happen, and simply deleting files does not remove them. At Elevate we manage the full lifecycle for clients: we plan the refresh, securely wipe or physically destroy the old drive with a certificate of destruction, and route the hardware to responsible recycling. You get the productivity of current machines, the security of knowing your data is gone, and a clean conscience on where the old gear ended up.