Sorry oli. Your post is great. This is the only thing I disagree with. Replacing tiles I dig all 4 corners out( grout lines, top left, top right, bottom left, bottom right)with a flat head screw driver. Then middle of each joint with flat head. Then batter with a hammer (concrete floor) if gyprock (for example) I make my snips the hammer and lightly batter. Generally speaking at least one point of the tile will give way and I work from there.