word choice - When are 止める, 停める and 留める read as とめる, やめる or とどめる?

When are 止める, 停める and 留める read as とめる or とどめる (and in the case of 止める, やめる)?

I think 止めてください could be read as both やめてください and とめてください, which I think could maybe be translated as "cut it out" and "please stop" in English respectively, but what exactly is the difference in usage and meaning between やめる and とめる?

Is とどめる usually written in Hiragana, and if not in what contexts do you use that reading rather than the others?

What exactly is the difference in usage between the three Kanji 止, 停 and 留? (Looking at the Google IME explanation, I think the 止 is used for generic "stop", 停 when used in reference to cars stopping etc. 留 I'm not 100% on, but I think it might have something to do with "making something stay"/"detaining" looking at the Yahoo J-E definition.)

Answer

The verbs やめる and とめる are different verbs, although related "in spirit", which is the only excuse for writing them with the same 漢字.

Try to think of やめる as "to quit", as in "to quit doing something" or "to quit work". やめる is almost always written in かな. For quitting work you are allowed to use 辞める.

とめる (written 止める) means physical stopping and it is thus clear from the context, whether 止める should be read やめる or とめる. You can quit work, quit smoking (たばこをやめる), but both are abstract concepts and cannot be stopped physically.

留める is more of a staying behind, as in 記憶に留める "to keep sth. in mind" and has little to do with physical non-motion, written 止, or stopping (at a bus stop, say), written 停.