The OTHER Kevin in San Diego wrote:

My "longevity" issue is with tubes of caulk or silicone sealant..
They never seem to last more than a week after I open 'em, regardless
of the measures I take to seal 'em up.

Lee Valley Tools sells some caps for tubes that look like tiny red
condoms. They're cheap -- a few bucks for 20-25, IIRC. Squeeze a tiny
ball of caulk or whatever out of the tip (supposedly to be sure the air
is out of the tip) then put one of these jobbies on the tip and unroll
it (they're about 1.5" long). When you need the caulk again, just roll
up the cap and it's ready to go. Afterwards, the cap can be reused.

I've had open tubes of silicone caulk, latex caulk and Liquid Nails that
have been fine when opened after being stored for a year in the basement.

Tove