I'm probably one of the guys that Al is talking about staying in it too long. I've spent 10's of thousands the last couple of years and had the worst 2 seasons ever, since I started.
A few things keep my interest up. The friends I have that do it, the pure competition I feel when I am able to race, and the feeling of accomplishment I feel when I occasionally win. If I do quit, it will be after I have accomplished what I came into the sport to do, win a National event. Or until my health or wallet won't allow me to continue. The money spent for bad results, will always p!ss me off. JMO