Hot take: cheap pine shelves taught me more about wood movement than 10 years in the shop
Built a set of 36 inch pine shelves for a guy in Reno back in March, glued and screwed them tight against the wall cleat, and by June every board had split right down the middle because I left zero room for seasonal swelling, so now I'm wondering how you all handle movement on painted built-ins where you can't hide a gap.