I use the fear of future clutter to try to keep my impulse buying down. Like sure, I could go buy a big 4K TV... but then what would I do with my old (still perfectly good!) 1080p set? I could upgrade the GPU in my HTPC, but I'd then have a 1060 I wouldn't have anything to do with.
I'm at a fairly comfortable place, where all my entertainment needs are met. When I get the urge to spend on something, I make myself balance the actual improvement to my life against the hassle of dealing with the clutter, and moral implications of creating even more hard-to-recycle E-waste.