I suggest
always reading the fine print when it comes to either file hosts or website hosting.
Middle of the page, under "Termination":
https://www.dropbox.com/termsDropbox reserves the right to terminate Free Accounts at any time, with or without notice. Without limiting the generality of the foregoing, and without further notice, Dropbox may choose to delete and/or reduce: (i) any or all of Your Files if your Free Account is inactive for 90 days; and (ii) previous versions and/or prior backups of Your Files.
Granted, 90 days of grace period before deletion is
very generous as far as
free file hosts are concerned. In fact, with the exception of the no-deletion policy of
host-a.net, I've not seen a better policy.
In the past I have actually found
dead links to downloads that were hosted on Dropbox. But I do not blame Dropbox. From what I recall, the files in question were some obscure mods for a rather old game, so I would not be surprised if over 90 days had passed since the last download. If blame is deserved, it would be the file hosting industry for setting the standard. After all, the industry just wants to encourage users to
pay for file hosting, instead of leaching bandwidth and space for free.
Edit:
A couple years ago I spent a few days with Google searches and reading through pages and pages of fine print on the
FREE Web Hosting website review site in order to find a free file host that did not delete stuff for inactivity. I was about to give up and conclude that such a site did not exist, until I finally found host-a.net.