Don't bash on the spend to improve phase. If I'd never bought overstable discs I never would have seen the merits of the flick, the tommie, the thumber, the skip, the flext shot etc. Without buying more putters I never would have realized that some fly better in the wind than others, and that there's a reason people prefer aviars to sonics. Without buying more mids I'd have missed out on the joy of having a really straight disc, like a broken in roc or a buzz, not to mention being able to shape a discs flight. If you don't update your technology you'll be stuck wondering why you can't get your stingray as far as I can throw a katana.
I have a whole bin full of discs. My bag is full but every few rounds I swap one or two out with the bin. I use the extras as loaners to get friends into the sport and I give lots of discs away to newbies and to family. Every now and then, I go back and realize the merits of a disc I had previously ditched, usually because I wasn't ready for it. I have more than a handful of discs that I bought thinking they'd be just what I needed, and they weren't. That's okay, in the bin they go. Part of the fun of this sport is I can buy every disc my heart desires and it's still cheaper than all the other sports I play. I've got $800 of ice hockey gear and it still costs me $20 every time I go play. I've got $1000 of ski gear and warm clothing and it still costs me $60 every time I go. $60 bucks of plastic keeps me happy for months and it doesn't cost me anything but gas to go to the course. Sure, you should really get to know your discs, but don't be afraid to try something new. Besides, it's fun to throw new plastic and see what it does.