If you’re not using a web host that performs its own daily backups then switch (I personally use thiswebhost.com and they’ve been fantastic so far). But never rely on the backups from your web host.
It may be relatively uncommon for web hosts to lose your data but they’re not immune to the possibility and even if they claim to perform regular backups you can never really know how comprehensive their systems are.
Use a web host that performs their own backups because it gives you just 1 more layer of protection, but don’t use them as a replacement for your own system. Think of them as a bonus.