if you have backups, check that you can still restore files from them. then make a new one today
if you don't have backups, do you have spare storage lying around? old DVD-Rs, a loose SD card, some unused free cloud storage? copy some of your files today, be they legal documents, family photos, your minecraft save. whatever matters to you. if storage is tight you may have to make some tough calls but please don't put it off just because you can't save it all in one go
it's world backup day (addendum)
if you have automated backups, that's great, this post was not for you. still, you should check that your backups are still being made and that you can restore from them