The only have I have ever attempted this was to be able to rescue a few tiles from one room of a discontinued pattern to use in another bathroom with the same tiles where I wanted about 40 more.
It is a thankless task, unless they are poorly stuck on.
My success rate was about 30%, and the task involved chipping off the tiles with a bolster then grinding the adhesive off the back.
Unless you have a similar scenario to mine, it really isn't worth it, as others have already said.