It depends.
I don't like routine that much. I don't eat the same thing for breakfast every day, and I don't always fly at the same height.
Of course it might depend on controlled airspace or cloud. it might also depend on the wind...if I go higher or lower am I likely to get more or less of a headwind/tailwind, and will the wind increase/decrease? Actually it rarely makes much difference, but I tend to work it out anyway.
If I'm not talking on the radio and no-one cares, I bimble along at whatever height I feel like, and vary it as I feel like. After all, why not? I spend enough time instructing and having to be - or teach someone else to be - at a certain altitude. So if I'm having fun, who cares.
I tend to go lower flying helicopters than f/w, but again, it depends.
I used to avoid 2000ft in crowded areas, but read so often that I should fly at 1800 or 2200 ft that I decided it would make no difference. And I once told an ATCO I was at 2200 ft, and he instantly told me to be at 2000ft...oooooo, too unconventional, was I?
Over the sea - as high as possible. Over woods, ditto.
I could go on but I think you get my drift.