I think all caulks need to be checked and redone after a period of time; just the nature of the beast. The exception would be if someone made a two part (resin/hardener) epoxy caulk that used a caulk gun that mixed the two parts, so the caulk would not just have stuff evaporate, but actually cure in place. This caulk would be a polyurethane mix so it would stretch and flex, but still keep a solid seal.
If I wanted to seal it and forget about it, I'd use Eternabond tape. In the time I've been on rv.net, I've read only one failure story that I remember, although EB needs to be applied as per directions since if the tape is stretched or it isn't pushed into place by a roller, the microsealant won't hold.