Yeah, for me, that decision comes pretty early on, probably in classical or medieval era. It depends a lot on what your opening situation is like (i.e. if youre on a large landmass, then domination is more viable because sea transport of troops is a pain in the ass. if you're on an isolated island, then science victory is more viable because no one will fuck with you and you dont need to spend hammers building troops, etc.). Also, it really depends a lot on your playing style. I prefer to turtle up and am more interested in min-maxing my own civ than destroying other civs, so sometimes I'll go through the whole game without a war. I virtually never start wars myself, only if some dickhead plopped his piece of shit city somewhere where it blocks my expansion.
I will say that in late game I will sometimes change tracks and alter my win condition. Sometimes I'm trying to win by science, but it turns out my culture is kicking ass because while I was waiting for these spaceports to build and launch satellites, etc. - i had a bunch of extra resources and so i made all these archaeologists and now my museums are bursting at the seams with artifacts, etc. So Ill just throw everything behind a cultural win including swapping in policies for tourism, sending trade routes to countries instead of city states, etc.
Sometimes, science and culture just drags on for so long that you just say fuck it, build 4 bombers, 2 tank corps and then blitzkrieg everyone off the map in 50 turns in late game.
