The new car is exciting for six weeks. The bigger apartment, a few months. After that, satisfaction returns roughly to where it was, and the improvement simply becomes the new floor against which everything next is compared.
This does not mean spending is pointless: it means some spending adapts and some does not. The research is fairly consistent that purchases which become invisible routine (square meters, objects, product tier) adapt quickly, while those buying time, health, relationships or experiences with a story adapt far more slowly.
This is the piece that turns a budget into a decision about a life rather than only about money. The useful question before a large purchase is not "can I afford it?" but "will this still matter to me in two years?".