How do I keep a computer maintained?

The short list that actually matters — updates, backups, storage headroom and dust — and the maintenance myths that waste time.

Difficulty: beginner
Time: 45 min
Read: 5 min

Short answer

Four things: keep it updated, keep a backup, leave at least 15% of the drive free, and keep the vents clear of dust. Almost everything else sold as maintenance is unnecessary, and registry cleaners are actively unhelpful.

Computer maintenance has a large mythology attached to it. The genuinely useful list is short enough to do in an hour a month.

Step by step

Keep the operating system updated.Security updates are the single most valuable maintenance task, because most successful attacks exploit something already patched. Set them to install automatically and let restarts happen.
Update applications too.Browsers especially, then anything that opens files from the internet. An outdated browser is a bigger risk than an outdated operating system.
Set up a backup that runs itself.File History on Windows or Time Machine on a Mac to an external drive, plus cloud sync for documents. A backup you have to remember is a backup you will not have.
Keep a copy off site.Cloud storage, or a second drive kept elsewhere. A backup drive next to the computer does not survive theft, fire or flood.
Test that the backup restores.Restore one file, occasionally. A backup nobody has ever restored from is an assumption, not a backup.
Leave at least 15% of the drive free.Both Windows and macOS slow down noticeably on a nearly-full drive, because they need working space. This is one of the most common causes of a computer that has become sluggish.
Clear space properly.Storage Sense on Windows or the storage management tool on a Mac. Downloads folders, old installers and duplicate photos are usually where the space has gone.
Review what starts automatically.Task Manager's startup tab, or Login Items on a Mac. Programs that launch at boot are the main reason a computer takes minutes to become usable.
Restart it weekly.Sleep is not a restart. A weekly reboot clears memory leaks, completes pending updates and resolves a surprising share of vague slowness.
Keep the vents and fans clear.Dust is the main physical cause of failure. Compressed air into the vents every few months, with the machine off. Heat shortens the life of every component inside.
Do not use it on soft surfaces.A laptop on a duvet or a cushion blocks its intake. Sustained overheating causes throttling first and hardware failure later.
Run one antivirus, not three.Windows Defender is adequate for most people and is already there. Multiple security products conflict with each other and slow the machine without adding protection.
Ignore registry cleaners and optimisers.They provide no measurable benefit on a modern system and some cause real damage. Much of the paid maintenance software category is solving a problem that no longer exists.
Do not defragment an SSD.It is unnecessary and causes wear. Modern operating systems handle SSDs correctly on their own. Defragmenting is only relevant to old mechanical drives.
Look after the battery sensibly.Avoid leaving a laptop at 100% permanently plugged in if it has a charge limit setting. Most modern machines manage this themselves, so enable the option rather than managing it manually.
Keep the keyboard and screen clean.A slightly damp microfibre for the screen, never a household cleaner, which strips anti-glare coatings. Crumbs under keys are a common cause of a key that stops working.
Set a monthly reminder.Check backups ran, clear the downloads folder, install pending updates, glance at free space. Twenty minutes monthly prevents nearly every avoidable problem.

Tips

Updates and backups are the two that matter. Everything else is a distant third.
15% free space. A nearly full drive is one of the commonest causes of unexplained slowness.
Registry cleaners and optimisers do nothing useful. Some do harm.

Common mistakes

Postponing restarts and updates indefinitely — Pending updates do not apply until a restart, so the machine stays vulnerable to problems that were fixed months ago. Most successful attacks use known, patched flaws.
Installing a PC optimiser or registry cleaner — They provide no measurable benefit on modern systems, and some delete registry entries that applications depend on. The category exists for marketing reasons rather than technical ones.

If it doesn't work

Computer has become slow generally

Cause: Full drive, too many startup programs, or pending updates — Fix: Clear space to at least 15% free, prune startup items, and restart to apply updates.

Fans loud and case hot

Cause: Dust blocking the vents — Fix: Power off and blow out the vents with compressed air. Keep laptops on hard surfaces.

Takes minutes to become usable after switching on

Cause: Startup programs — Fix: Disable everything non-essential in Task Manager's startup tab or macOS Login Items.

Storage full and unclear why

Cause: Downloads, caches and old installers — Fix: Use the built-in storage management tool, which shows what is actually taking the space.

Backup drive is full

Cause: Versioned backups accumulating — Fix: Both File History and Time Machine prune old versions automatically once full, but a larger drive gives you more history.

Questions people ask

Do I need paid antivirus?

For most home users, no. Windows Defender is built in and performs well in independent testing. Running two security products at once causes conflicts rather than better protection.

Should I defragment my drive?

Only if it is an old mechanical hard drive, and even then the operating system handles it automatically. Never defragment an SSD — it achieves nothing and adds wear.

How often should I restart?

Weekly is a good habit. It applies pending updates, clears memory leaks and resolves a lot of vague slowness. Closing the lid puts it to sleep, which is not the same thing.

Are PC cleaner programs worth it?

No. They largely delete temporary files you could remove with the built-in tools, and registry cleaning provides no benefit while carrying real risk of breaking software.