I’ve come up with a strategy (for myself) to keep from accumulating clutter. When buying something, I pretend the price has another zero on it, or is double the price. Then I ask “Will I pay this price?” My answer tells me how much I really want the item.
It may be easy to spend $20 for a t-shirt; do you love it enough to pay $200 though?
TIP: Especially apply this method if an item is FREE. I once told a client “Free = trouble.” Sometimes, our sound reasoning disappears when we see “free.”