If you only have one copy of your data, it’s already lost. If you care about it you need a backup. Every website needs a backup as well. There are plenty of great backup plugins however I highly recommend using a backup service not a plugin.
Problems with backup plugins
There are plenty of backup plugins to pick from however I wouldn’t rely on any of them for regular backups. Backup plugins only run if your website is healthy. If there is a problem with WordPress or your web server, it’s likely your backups won’t run and worse yet you won’t see any notifications that there are problems.
Backup services are your friend
Backups services run from their own platform and connect to your WordPress site over FTP or via it’s own WordPress agent plugin. If there are any issues preventing the backup you’ll be notified. This adds an extra check to make sure things are running smoothly.
I personally use a combinations of my own backup script and ManageWP. Each method operates as its own service as the backups are initiated offsite and provides some level of notifications if things aren’t working. A few other popular backup services are VaultPress and CodeGuard.