Droplets are great, and I like the ease of use of Digital Ocean. But, as far as server backups go, I've never liked managing these, so I use an external data store and DB server. In my case, my instance is wired up to an Amazon S3 bucket, and an RDS database. If you set it up this way, there is no need to worry about backups of the application server.

I could nuke the app server, change hosting providers, or if there was a hardware failure or whatever, it won't matter. I can always spin up a fresh server, and plug back into my external DB and data store.

You can add disk-level backups to droplets, IIRC it will keep four weekly backups, for +20% price to the droplet

Its a paid add-on iirc