I've been struggling with the acquisitions as well so I try to figure out why I want that next thing and go down the line of necessity vs. want.
The Fact is that I could get great shaves out of what I have. That next thing will not affect my shave by much but it'll make me happy and excited during the honeymoon phase.
For soaps, I have enough to use for the next 10 years. I'm resorting to samples ONLY because full tubs are too much at the moment.
For razors, I have many tools that shave well. Not really interested in new ones unless they're budget-friendly and solidly built. (Got a Fatip Lo Storto recently..)
For brushes, this is my weakness. I see a beautifully turned handle and my mind goes crazy. I'll reserve these purchases for special occasions.
And the rest, I could restrain pretty well.
I think new purchases is part of what makes this hobby fun but one of the main goal is to great shave which I can get with my current products. I'm currently taking it month by month and tracking my purchases. I'll hold off for several months and then designate one for purchases. I just remind myself by looking at my purchase amount and keep myself somewhat sane.
This all said, I've been still purchasing a little too much for my liking so it's a working progress.