I am pretty sure I tear through nibs a little faster than most- I looooooove a fresh new, sharp nib! Before I chuck them, however, I gently look between the tines by vertically separating them, and if there's dried ink in there, I clean it out as much as possible. Again... gently. Sometimes this will earn me extra time with it, but if it's a real chore, then, like Janis said, it's not worth the trouble.
It's worth noting, since you've mentioned in posts that you've been using the G nibs, the life of a nib depends on what it is. The Nikko G will last far longer than the sharper, more delicate nibs, like Hunts, Principals, Etc. Your paper will also factor in (rough vs. smooth), how much pressure you're applying, and the ink you're using (is it a nib eater, like Iron Gall or Yasutomo?).
Lots to consider! But, the more you go along, the more you'll be able to quickly recognize the need for a new nib. Always keep lots on hand!