Pretty soon you're a bit poorer and your luggage is a lot heavier.
A few years ago I decided to really be aware of what I spend on souvenirs especially from places I've been to several times. This didn't mean ruling out souvenirs entirely, but instead focusing on something that had meaning to me and I could really use. That item for me is jewelry. I try to buy one piece of jewelry from each country so that when I wear it, I can remember my time there. My price point is pretty low (under $50), and it doesn't add much weight to my luggage. The bracelet above is from L'Accademia. One of my classmates here had one, and I thought it would make a very nice memento of both my time in Florence and of taking classes. It was 8 euros, so in addition to being pretty, the bracelet hardly breaks the bank.