I've still got all my resistor, transistor, diode, zener diode spares. From time to time I'll make a little circuit up to do a specific task. These days you can get virtually everything pre-made from Amazon amd other outlets.
A few years ago I knocked up a tiny door alarm for the freezer. I had to fit it between the small panels on the front. To this day it still works and no more accidental defrosting with the door being a few mm open