I've never bought a fish that would get too big for my tank (but it wouldn't let me complete the poll if I didn't choose a second answer so I put return to LFS), if I ever wanted a big fish I would get a big tank first, its just something everyone should do I think, its called being responsible. All well and good thinking you will get a bigger tank, and many people do this successfully - get a fish small then get a bigger tank later, but I always think what if something comes up, what if I need that money for something else? Then you are left with a huge fish, though no fault of its own thats going to be in a tank too small and is probably going to be hard to even give away.