How often should you back up? Recovery point objectives (RPO) in plain English

How often should you back up? The honest answer is: as often as the amount of work you can afford to lose. If redoing an afternoon's work would be a nuisance, back up at least every hour. If losing a single change could cost you money, back up continuously. For most home PCs, once a day is the bare minimum.

IT professionals boil this idea down to a single target called the recovery point objective, or RPO. This guide explains RPO and its partner RTO in plain English, shows you how to work out the right backup frequency for your own files, and covers the question most people forget to ask: how long to keep old backups.

The short answer

What is RPO (recovery point objective)?

Your recovery point objective is the most data you're prepared to lose, measured in time. It answers the question: "If everything failed right now, how old could my most recent backup be before it really hurt?"

Say you back up once a night at 11pm and your drive fails at 5pm the next day. You lose 18 hours of work, and in the worst case you could lose almost a full day, so your effective RPO is 24 hours. Back up every hour and the worst case is an hour. Back up continuously, as files change, and it can be a matter of minutes.

RPO is a target you choose, not a feature you buy. Your backups then have to run at least that often, reliably.

What is RTO (recovery time objective)?

Your recovery time objective is how quickly you need to be working again after something goes wrong. RPO is about how much you lose; RTO is about how long you're stuck.

For a single lost document, recovery takes minutes whatever you use. For a whole PC, it depends where the backup is. Restoring from a drive on your desk is usually quick. Downloading a large backup from the cloud is limited by your internet connection and can take many hours for hundreds of gigabytes. If you couldn't cope with a day or two without your PC, keep a local copy for fast restores as well as a cloud copy, as the 3-2-1 backup rule recommends, and consider having a spare laptop ready.

How to work out your RPO in four steps

1. List what you work on. Documents, spreadsheets, accounts, design files, email, photos, databases.
2. Ask what losing an hour, a day and a week of changes would cost. Count the time to redo the work, the money involved, and anything that can't be redone at all, such as a signed contract that arrived by email or photos from an event.
3. Pick the shortest gap you could live with. That's your RPO. Most people land on "an hour or less" for work files and "a day" for personal ones.
4. Check your tools deliver it automatically. A nightly schedule on a laptop that's asleep at night doesn't deliver a daily RPO. Continuous backup, or a schedule that catches up as soon as the PC wakes, does.

Backup frequency is only half of it: retention

How often you back up decides how much you can lose. How long you keep old versions decides how far back you can go. The second matters more than people expect, because many problems aren't noticed straight away:

• A spreadsheet is saved over with the wrong figures, and nobody spots it until month end.
• A file becomes corrupted, and every later backup contains the corrupted version.
• Ransomware or an intruder sits quietly for days or weeks before doing damage.
• Someone deletes a folder they think nobody uses, and it's needed next quarter.

A sensible retention pattern keeps lots of recent versions and fewer older ones: for example, hourly versions for the last day, daily versions for the last few weeks, and weekly or monthly versions going back further. That way you can recover this morning's version of a document and last spring's.

Continuous vs scheduled backup

Continuous backup watches for changes and backs up new and modified files shortly after they're saved. It gives the smallest possible gap and doesn't depend on the PC being on at a particular time, which suits laptops. A good implementation works quietly in the background and eases off while you're busy.

Scheduled backup runs at set times, such as every hour or every night. It's predictable, and it can be timed to avoid busy periods or metered connections. The risk is that the PC is off, asleep or offline when the time comes round, so check that missed backups run as soon as possible afterwards.

Plenty of people use both: continuous cloud backup for their files, plus a scheduled local backup or an occasional system image.

Common backup frequency mistakes

• "I'll back up when I remember." Manual backups get forgotten in exactly the weeks that matter.
• A weekly external drive routine. Better than nothing, but a failure on Friday afternoon loses the whole week.
• Schedules that never run. Laptops asleep at 2am, PCs switched off overnight, a backup drive left in a drawer.
• Backups that fail silently. If nothing tells you when backups stop, you'll find out when you need one. Check the date of the last successful backup regularly.
• Short retention. Frequent backups with only a few days of history won't help if the problem is discovered next month.

If the worst has already happened, our guide to recovering deleted files on Windows walks through your options in order.

A note for businesses

In a business, RPO and RTO are business decisions rather than IT settings. Agree them for each important system (the accounts package, the shared drive, email) and write them into your recovery plan. They also shape your ransomware defences, because keeping versions from well before an attack is what lets you restore cleanly. Our ransomware checklist for small businesses covers the rest.

How EverSafe handles backup frequency and history

By default, EverSafe backs up Windows PCs continuously, watching for changes and backing up new and modified files as they're saved; you can switch to a schedule if you prefer. Open files such as Outlook data files are included through Volume Shadow Copy, and only the changed parts of files are uploaded, so frequent backups stay light.

Version history follows the pattern described above: hourly versions for the last day, then daily versions (how many depends on your plan), and on plans with unlimited versions, weekly versions for a year plus monthly versions. See the features or compare plans.