Whether you have to lower during the Winter or not depends on a couple factors...
1--How low was it drained at the start of season
2--How much precipitation do you get over the Winter.
Personally I am in Heathers situation with a potentially high water table so I try and keep the pool water level as high as I can. Usually I start toward the bottom of the skimmer and try and not let it get above the top of the skimmer opening all Winter. This usually means draining periodically. Because it is usually a block of ice I do it in small increments, about 1/4" max, then let it sit for a few days before doing it again. Have to be real careful because of the ice block and the possibility of damage to steps and return jet penetrations. I likewise used a mesh cover but not anymore....too much of a hassle so it stays uncovered.
Hope this helps.
Al