How to know potato is done without poking it to check softness? I can never get potatoes boiled just right. They're either over or under cooked.  When I think they could be about done, I poke one or two with a knife but then that one splits and cooks faster than others.  It also spills the potato juices in the water, and I don't like to do that, which is why I boil whole potatoes and not sliced.
Is there a way to know potatoes have attained just the right level of doneness without poking them with a knife or fork?
Great question easy fix as I had the same issue. Set aside or add  a couple extra  chunks or potatoes that is just for testing. When you test a chunk toss it, the test potatoe will be representative of how the other potatoes are cooking, it allows you to puncture without compromising the rest of the batch.