I always have problems with applicators and necks getting crammed up with dried glue using Zap-A-Gap. I have found that if you leave a Micro applicator on the bottle and just leave it uncapped, it takes a really long time for the glue to harden inside, and the glue stuck in the applicator usually runs back down into the bottle, but it sometimes glues shut. If the applicator gets jammed, just cut the tip off and you should be back in business. I don't think I've ever used more than half a bottle before it becomes pretty useless, but at least replacing it is fairly cheap.
I may give the Loc-Tite stuff a try next time around. Seems to have the best applicator and gets good reviews from experienced tiers.
Clear nail polish is pretty good, but finding a fine enough applicator can be a challenge. I guess we can always use a toothpick or something for detail applications....