Always keep a backup of the site - both server files and DB export off site. Canalplan for example is backed up onto about 4 different machines and also onto a backup disk on the main server. So that’s 83GB for the main site, 62GB for the tile server and 1.5GB of compressed DB export
One of the big problems with forums is that if the software becomes unsupported then you either have to shut down, migrate, or keep running on old software which might have security issues or just stop working with later versions of things like php.