This is a tool you never even knew you needed until you had it. What an amazing, helpful bit of kit.
I would NEVER have bought one until I borrowed one. It enabled me to remove individual tiles by cutting the grout line, chisel off the old grout thus saving the tiles to re-use and chase the Celcon blocks for the cable runs!
I've just recently used mine to trim 4"x2" timber projecting from a padstone.
Used to cut SQUARE holes on floor boards to drop trunking through without lifting the boards.
Cutting PVC trunking.
The uses are endless.