Common?

If we're talking just at home, I'd have to disagree. But yeah I think probably fairly commonplace for industrial use maybe?

I don't recall ever seeing a single one being sold back when I used to be sent out for lightbulbs, because incandescents popping so often were a designed feature and as a kid I wasn't going into proper hardware stores.

40w and peeeerhaps 60w would be the most common ones, I'd say. Might vary ofc depending on where and who and when. But for like general house use in Finland I'd say those were definitely the most common ones. I'm guessing that's sort of why lamps have the "most 40w" so that people use at most the 40w incandescent if someone still has those? Because newer ones draw so much less, there's no need to design the schematics so that it can take 120w when most LED bulbs range from 7-15.

I'm talking 40% of my arse so please do correct me for the mistakes I think I must have made