Just adding that you should make backups anyway, possibly on some sort of media that is offline and in a different location. No cloud service is really safe. I'm not saying Dropbox or OneDrive could disappear tomorrow, but yeah, they technically could, or they could lose part of your data. Even Gmail lost some user emails a few years ago. How many people do you know who backup their mailbox these days? :-)

There's also silent corruption and bit rotting that may happen locally and which you wouldn't notice on any of those services. Particularly if you use old filesystems such as HFS+: there are quite a few stories of people losing pictures or finding artifacts in jpg/raw files years later.

I'm sure you're not, but if by any chance you're relying on Dropbox versioning or whatever similar "backup solution" please consider alternatives.