I worry about off site backups - what if they aren't there in a year or 2 when I really need them?
You would have notice it gone by then. The idea is that you rotate a backup to an off site location. You make a copy take it some place, then bring the old copy back and over write it. This way you touch the off site copy every week or whatever your cycle is.
You can't expect any backup, no matter what media type you use to be good after a year. Yes you can get lucky but don't depend on luck.