My folks never smoked, but both of my grandfathers smoked. So did some friends of my folks. Thus ashtrays were around in some of the places we'd visit. At the time they seemed rather common whether a glass or ceramic tray on a table or a metal tray on its own stand. Cars had ashtrays too, and not just one thing in a center console, but built into the inner door handles.
When my mother's place of work had an addition built sometime in the 1980s there was an open house to show off the place. While not large by big city standards, it was a fairly impressive building and sort of in the country. From the second or third floor the view through a large picture window was great. In the evening, when the open house was, the view was something like you might expect to see from a futuristic spaceship cruising low, about to land. And then I looked around and saw the ashtrays and it was a rude snap back into the 20th century as the effect was destroyed. Since then the place, like many others, has gone smoke free.
I'm not sure when the No Smoking Section started showing up in the area, but it was welcome. Eventually one airline declared that domestic flights of less than two hours would be no smoking. Even though we didn't fly commercially, we took this as a sign of progress.
Since then things have changed even more. Many places are non-smoking and others often have non-smoking sections that really are non-smoking sections, not areas where no tobacco is burned but where smoke fills the air all the same. I've been on a few commercial air flights and have never seen the No Smoking signs off. Unless I'm at a restaurant that is really a bar (Minnesota law requires food be available if alcohol is served; you can't have just a bar and so must at least have sandwiches as well.) it's unusual for me to encounter smoking inside a building.
The transition has actually been fairly gradual. I didn't realize quite how much I take for granted that I won't encounter tobacco smoke until I happened across a couple ashtrays in some store and it took a moment to realize what they were. They were anachronisms to me.