Need something compact with simple controls

I am trying to narrow down what to look for rather than asking for one magic product. My priorities are compact size, very simple controls, clear status feedback, and easy-to-find replacement parts.

What criteria would you put first so I can eliminate options quickly?

Start with the replacement-part situation and interface. If either is confusing, the product will probably keep creating friction after the initial setup. Then compare size and carry comfort among the options that pass those first two checks.

I would also check whether the controls can be locked or are hard to trigger accidentally. “Simple” is less useful if the device changes settings in a pocket.

For parts, write down the exact family name and revision before buying extras. Similar names are where compatibility mistakes start.

That gives me a much better filter than staring at feature lists. Thanks.