Hah! Preposterous. Nothing is too expensive...
As long as my wife doesn't find out.
Actually, I like the way Pete frames his answer around relativity. Between a large stash, lots of reference material and aftermarket "stuff", I'm sure I've spent "too much". But my hobbies before modeling were drag racing, muscle cars (primarily 67-68 Camaros) and building (and rebuilding) race engines, transmissions and rear ends...and all the associated tools and space. When kids started to come along (4), I had to change hobbies.
So the expense of modeling in (mostly) 1/35th scale, relative to my former hobby, really seems like a drop in the bucket to me.
Plus, the time I spend modeling, takes away from my time to spend on other expensive hobbies. Like golf...or gambling.
Hmmm. Where's that next Nationals?
Tony.