When i am talking about stopping unit production, i do not mean stopping in the middle of a war you have to win. I mean after you produced at least 50, maybe more than 100 knights and conquered say 30-40% of the world (if you manage to take half, you can push trough at all costs to reach the 66% probably), but now with gunpowder the defenders you meet are too strong to proceed and between them are maybe the french. In that case, you certainly can take a break in your unit production until you have a new opportunity. The workers are interesting for sure. When i am on a big continent, i want a long and straight road crossing that continent. One long highway for my armies to follow. When there is nomansland between you and the first enemy, it is good to start building that road before you move out. Usually i like to have 2 stacks of 3 workers, together, they can build 1 road tile every turn. In captured enemy territory, try to gather the captured slaves to make the needed connections between the extisting pieces of road there as fast as possible.