I'm middle class. We have a safe deposit box where I keep stuff that would be a pain in my ass to replace in the event of a fire/flood/etc.
Said items are titles to my vehicles and home, my marriage license, the will of a family member I've been entrusted with, birth certificates for my self and family members, and a couple of keepsakes for the kids that I'm very long on. It only costs me about $80 per year, and it brings me a lot of peace of mind. I have photocopies of all those docs at home, because you rarely need the real thing.
A local bank near us provides a free one as long as you keep $100 min balance. So ends up being very cheap offsite backup to store important documents, a backup hard drive of most precious data, etc.
Said items are titles to my vehicles and home, my marriage license, the will of a family member I've been entrusted with, birth certificates for my self and family members, and a couple of keepsakes for the kids that I'm very long on. It only costs me about $80 per year, and it brings me a lot of peace of mind. I have photocopies of all those docs at home, because you rarely need the real thing.