I like the YYE trick ladder and keep an eye on the Trick-a-week topic for anything that catches my eye and seems attainable (probably one every couple-three months).
As to why not to spend too much time hoarding throws of any price: I find that I waste a lot of time trying the tricks I already know on different yoyos just to see how they feel or to give each one play time to attempt to justify the purchases. Time that would be better spent sticking with one yoyo and learning more. I wish I could control the hoarding impulse and follow the aforementioned advice, but it’s a struggle (as we all know).