My jar doesn't get any direct sunlight, only indirect. Its definetly easy to tell the changing season though, I get intense hair algae for weeks until the light stabilizes a bit. As for water changes...I think the last one was 4 months ago? As for adding dirt, be careful, you will get inevitable greenwater and intense clouding. It goes away after a while (I did 3 daily water changes in the first week to take care of clouding from the dirt) fortunately, and the snails mostly take care of algae on the sides of the jar.
The jar is about .5 liter, I took the pics under a desk lamp. When I added the extra substrate, I pulled a couple D. sag for one of my tanks...and the entire substrate came up. Hence adding gravel, hahaha