I challenge myself by saying that I can't go shopping or even look at new stuff until I have completed so many LO's (even at that I still can't tell I used anything)usually by then I am still in a gotta use it mode and feel so good about using up some on my stash that I just want to keep going.
Then old habits creep back in and I find myself shopping but usually for less stuff and for something specific.
I also find that because I have too much stuff to choose from that it does distract me from being creative. Lots of times I will just grab a specific paper pad or single pp and embellies that all coordinate put them in a organizer and that is all that I will work from.
Once I whittle that down I restock and start again.
I find that I am more cretive when I have less choices.
It is like putting some the toys away that your children don't play with and then when you rotate them they act like they have never played with them before. HTH