One of the tools I bought was a Fluke Clamp meter, the 325 model. This thing gets used extensively, like all the time.
It has a temperature probe so I even end up using it to monitor temperature of batteries, engine coolant, you name it.
The Clamp (Amps consumed) meter is very useful and allows me to work out where the current really is going and if it is going.
The only thing that gets used as much would be the testing probe I got on a heavy discount along with it… thought I would never use that. go figure. It’s so useful.
Doesn’t need to be a fluke, they are good but also expensive, but get a good one that is waterproof and will stand up to the abuse all tools get on board.