Not sure but i suspect 'return time' is the estimated dig time for the node, which should remain '/=' so that it gets longer. https://github.com/minetest/minetest/blob/f1d2bc096573627b2bbb1aa48e856f7a76e4790a/src/game.cpp#L4012 https://github.com/minetest/minetest/blob/f1d2bc096573627b2bbb1aa48e856f7a76e4790a/src/game.cpp#L4030 https://github.com/minetest/minetest/blob/c252ed506eb8324fbdea4b632116c2c7d06a8c9c/src/tool.cpp#L207 The change to 'result wear' below seems correct and a bugfix.