1. Heat

This is factor number one, and by far the most underestimated. An electronic component that constantly runs at high temperature ages faster: the thermal paste dries out, the fans wear down, and the machine ends up throttling itself so as not to burn out. A computer that becomes very slow only after an hour of use isn't a software problem: it's a machine that's overheating.

The things that matter: dust the air vents several times a year, never put a laptop on a bed, a sofa or a blanket — the fabric blocks the air intakes underneath — leave about ten centimetres of clearance behind a tower, and have the thermal paste redone every two or three years on a machine that runs hot. In our climate, this is routine maintenance, not a repair.

2. Humidity and salty air

Humidity alone is rarely fatal to a machine that's running: the heat given off by the components keeps the inside dry. The risk appears on equipment that's switched off and stored for a long time in a closed, unair-conditioned room: condensation sets in, and on circuit boards it eventually attacks the contacts. Near the coast, salty air clearly speeds up the process on connectors.

The things that matter: switch on a stored machine from time to time, rather than leaving it in a cupboard for months; store external drives in an airtight box with a moisture-absorbing sachet; ventilate the room where the equipment works; and if you live facing the sea, get into the habit of cleaning connectors and checking network sockets, which turn green before everything else.

3. Power cuts and surges

This is what we receive most often after a storm. A clean power cut switches the machine off abruptly: if it was writing to the disk at that moment, the system becomes corrupted — this is a very common cause of Windows machines that no longer start up. A surge, on the other hand, can destroy the power supply, and sometimes the motherboard with it.

The things that matter: a surge-protected power strip for all your computer equipment — a few tens of euros against the price of a motherboard — and for a professional workstation, a small UPS: it holds out for a few minutes, plenty to save your work and shut down properly. Unplug physically during a major storm: no surge protector withstands a direct strike. Think about the internet line too: the surge often comes in through there.

4. Hurricane season

Once a year, the question is no longer wear but total loss: flooding, roof damage, a long power cut. No setting protects a computer from a metre of water. The only protection worth anything is a copy of your data kept away from home, online or with a relative.

As an event approaches: back up, unplug everything — mains power and the internet line — raise towers and external drives off the floor, move equipment away from windows, and take the backup drive with you if you evacuate. After it has passed: don't plug in a device that got wet, even if it looks dry. Have it opened and dried properly first; restoring power to a damp board is what finally kills it for good. How to keep your files safe →

A yearly service, in practice

Once a year, ideally before hurricane season: a full dust-out, checking the fans, checking the state of the drive, testing a restore of a file from the backup, and checking that the surge-protected power strip is still working — they wear out and become plain power strips without warning. It's an hour of work a year, and it prevents a good share of the emergency call-outs we see.