I build apps out of spreadsheets and I’ve run out of ideas. What should I make next?

Three that people would actually open every week: 1. Home maintenance tracker: air filters, car oil, smoke alarm batteries, warranties. One sheet the family already edits, and the app nags when each one is due. 2. Job status page for small service shops: the owner updates a row, the client opens a link and sees where their job is, no login. Clients ask "how is it going?" more than anything else, I hear it every day in my studio. 3. Pantry list with expiry dates that warns you before food goes bad, shared by everyone in the house.

How about an app for coordinating things that neighbours usually share: ladders, drills, pressure washers, camping equipment? A simple spreadsheet could track who owns what, who's borrowing it and when it's due back. It's the sort of thing a small community might actually use without wanting complicated software.