For individuals running Dropbox, the biggest challenge is often working out how to maximise your free space. But business users who have paid for the service may experience a different issue: it seems Dropbox doesn't cope so well if you have more than 300,000 files.
Dropbox user David Burrows describes the issue in a post for Medium. It's revealed in an error page that shows up for users who have paid for extra storage and who but up against that limit:
While relatively few people are likely to store 300,000 files, it could potentially be an issue for developers storing a large number of versions (as it was for Burrows). Individual files might be small, but it seems it's the number rather than the size that's the issue. Something to bear in mind if you're a heavy-duty Dropbox addict.