Hi Les,
It'll last for years IF you keep the tip clean and capped. A good thing to do is to wipe the tip off with a paper towel before you snap the cap on.
If you don't keep the tip clean of glue, eventually dried glue will prevent the cap from sealing, and it'll dry out the contents of the bottle.
Zap a Gap is also waterproof, so it's great for using on flies.
I used to work for the largest East coast distributor for Pacer Technologies products, and was responsible for all returns - I'm very familiar with their products. They made another CA adhesive that was even better (Flexi Zap) - it was flexible when dried, and had a stronger bond strength.
Pacer makes accelerators that can be sprayed on to dry the CA in a second or two. Beats waiting for the stuff to dry completely, but you have to be careful to not use too much - it can create a white haze on the glue. Neat stuff.