You'll need an Amazon Web Services / S3 account to get started. Grab your access key and security key from the security credentials part of your account. Download / install the backup plugin (here it is on wordpress.org - search inside WP for "automatic wordpress backup" and it should come up).
You choose what to backup. You really do want to check all the boxes -- your database, all your files, plugins, themes, uploaded content, etc. On the site in which I have it installed, each backup is about 100MB.
Backups are kept for a month and then deleted, and monthly backups are kept for a year. At 100MB / backup, that's about 3GB (plus a bit more for keeping those monthly backups). At Amazon S3's pricing of 15¢ / GB, that's.... under 50¢ / month to have your site backed up every single day.
You can restore directly from within the interface as well, so this is a pretty turn key system. The UI is all in one page and a little clunky, and I did make some comments on what could be improved:
- In general, I would split the one big page into several tabs. A backups tab, a restore tab, and so on.
- if you add a progress indicator, or in general display a floating message that says “backup in progress”, then people will understand that a backup is happening.
- I would also do an immediate check against the access key / secret key and put in a green checkmark to indicate that it has connected correctly – with the secret key hidden, I’m always unsure if I’ve cut / pasted it correctly.
Of course, what about VaultPress, the commercial service? Well, in beta, they're charging $15 / month per blog at the Basic level, $40 / month for Premium. Or, um, 30x - 80x more expensive than doing it yourself with this plugin and Amazon S3. Their FAQ says that they are also doing security monitoring -- aka figuring out when your blog is hacked. And yes, most people are going to have to spend some time figuring out the Amazon interface and so on. But I really can't see how they can keep pricing at this level with this kind of free plugin available.
Are you backing up your site automatically? Amazon S3 and plugins like those above make it automatic and inexpensive.