[MarkJames]

Which 100% silicone caulks have a long shelf life? I realize they go bad (and sometimes won't cure/harden when old) but I'm an occasional user and it would be great if what's on hand can be trusted in a pinch.

For what it's worth, I found a small tube of 10 year old, at least, previously opened silicone in a tool box and decided to test it out of curiosity. Darned thing was still good and cured up as it should. (Now if I could only find the tube to see what it was.)
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[tedanderson]

Anything in the plastic squeeze tube seems to last for a while. Also, I use silicone in a pressurized can. The instructions say that you should store it by spraying out a 3/8" to 1/2" bead and then let it dry on top of the can so that it acts like a tightly sealed cap that can be pulled out of the nozzle when you are ready to use it again.

Even with the standard tubes that go into the gun never really go bad. You just have to be persistent with getting the "plug" out of the nozzle.

 

[Robie]

I don't even bother keeping them around long anymore. If I've used 1/4...1/2 a tube, I may keep it for a few days in case another job pops up. After that...they get tossed. By the time I get the nozzle cut enough to pry out the dried stuff, the nozzle is no longer any good. The frustration and the time just aren't worth ikt.

 

[MarkJames]

I don't even bother keeping them around long anymore. If I've used 1/4...1/2 a tube, I may keep it for a few days in case another job pops up. After that...they get tossed. By the time I get the nozzle cut enough to pry out the dried stuff, the nozzle is no longer any good. The frustration and the time just aren't worth ikt.

The tube I dug up had a screw cap. No unplugging whatsoever. I'll have to find that thing.