Basic blender went bad (motor ran but spindle wasn’t rotating). I wanted to disassemble to see if it could be repaired. Three of the four screws were Phillips head. I had to cut the casing open in order to discover why I couldn’t unscrew the fourth. It was a slotted spanner.
That’s more than some sockets or crescent wrenches I have from sets. I don’t know that I’ve ever used an 11mm of either.