I replay the "Metroid-vania" Castlevanias every few years (SotN, GBA/DS games), and one of my goals is always maximum map completion... obviously not required for actually beating the games, but I only consider the game completed if I get all the rooms on my map.
More specifically for SotN, I also gotta get the Crissaegrim + Medusa Shield otherwise am I even playing the game properly?
Some of the others I try to get all the doodads: cards, souls, glyphs, whatever. Some are a bit more annoying than others, so sometimes I'll skip out on the really annoying ones if I don't get it done before filling in the map.