When I were a lad, we had 4 types of bulb in the house – all bayonet type, 40 watt,65,100 and candle bulbs. That was it, a few spare in the cupboard. Now we have bayonets, Edison large screw, small screw even bare wire ones, and don't even go down the pretty flickering ones, ones for ovens, fridges, LED, Halogen etc etc. AND don't forget low voltage ones
If that wasn't bad enough, you often have to buy packs of 2 or 3.
The lighting world has gone MAD !