Originally posted by dneira29 And sometimes I just feel it build up so much that I need a release.
That about sums it up. Get a new lens, feel that your gear is complete for a while, enjoy shooting with what you have but feel something lacking when comparing to other pictures, wanting that one lens more and more, decide that you don't need anything else, buy the lens, rinse and repeat.
Sometimes just looking at what is offered on the (used) market makes me snag something if the price is right... I can prevent that by keeping busy enough so I don't even have time to keep an eye on prices, but every now and then in a boring minute I'll have a look anyway...