You use less colors when using too much colors is actually an issue with your art. Like if you actually notice inconsistency with the art overall, colors and its surrounding shades dont fit, etc. Your goal is not "to use a max of 3 colors", it is to make "good art". You've got good art yourself, Dylan, and a good palette. But the need to comment on everyone's GFX saying "less colors" seems a bit unnessesary for me unless it really does need less colors.

...but thats just me. I'm not a gfx designer or anything. I may just be talking out of my ass.