The wife was complaining about the kitchen timer being unreliable. I thought how can such a simple thing be in unreliable?

I changed the battery - all good - or so I thought until I put it on the counter top a bit roughly. Any jolt was causing the battery to disconnect and the timer to reset.

A Scrabble through the junk box to find an electrolytic which would fit in the case (100uF) and it's all fixed. You can take the battery out for 10s now 🤣