Tracking my pantry in my bullet journal showed me how often I buy duplicates | Bullet Journaling - Freelance Forum - The Community for Independent Professionals
Try doing the same with my spice rack. I always ended up with multiple bottles of oregano because I forgot I had some. Now I snap a quick pic of the shelf before I go shopping. It stops me from buying stuff I already have. My grocery bill is lower, and I waste less food. Simple fix for a common problem.