Around here it's usually done only the night after games. I've been to one tourney in a smaller complex that they watered and drug the fields about every other to every third game. But I have not been to hundreds of tourneys either.
The field needs lined after every game. That is simple to do. Also, if repair is needed to the batters box and pitching lane, that should be done also.
The problem with lining the field without dragging it is that no 2 lines are exact and all of a sudden there are 2 lines. In my opinion you are better of leaving the lines alone if the field is not dragged. The exception is that if the batter’s box is a mess you can rake the old lines away and restripe.
I am happy if the pitching plate and bases are the right distance.