I don't have too many slow days and I don't notice a difference from year to year if I'm being perfectly honest. Granted I'm in northern WI and have lake after lake to fish on. There are some lakes that seem to just not produce much until late ice. If a lake does not produce and is slow I move on to a different lake. Once I find spots they seem to produce year after year at the same time. I always take pictures of fish so I can look at the dates. I also hole hop much more than other people, I will start out by punching 20 holes and try them (less ice is great in my eyes). If no fish I move on. I don't waste more than 30 seconds in a hole without a mark on the vexilar. If they are there they will at least swim up to look at the jig. I don't even put in tip ups until I catch a few fish jigging and know they are in the area. Easier to punch a few holes, jig them quick and if nothing, move on. I see many guys just sit in one place catching nothing quite often. I call them 'settlers', which I took from the DirectTv commercial.
Case in point, last weekend 3 of us got 75 perch and 2 guys fishing with us who basically sat in one place and did not move much got 12 total. We moved to stay on the fish, they didn't. We threw quite a few back too. Since I have started hole hopping more I have had mostly good days. Its amazing how at times one of us can be catching them one after another but another guy 15' away doesn't mark a fish. Have to find that hot hole!
The worst is when a settler comes up to ask how we are doing and they say they have 3 fish and we have gotten a few 100. I usually say its slow too LOL. Have to move to find them and stay on them. Good exercise too.