How fast or slow they come off or go on is usually dependant on how wide awake and alert you are. The FEL usually takes me only a couple of minutes in either direction...it's a piece of cake. The 'hoe takes a little longer, but only because I don't do it that often. The time also varies if you have the 3pt to put on or off, too. Easy job, but like anything, it takes a few minutes to do.
The MMM is the "hardest" to remove and install, only because it's a little more awkward to deal with. Using the FEL to lift the tractor a little while sliding it under or out makes life a lot easier and having a flat and smooth surface to do it on is even nicer. (I don't have the latter and have to do it on the stone driveway)
All in all...none of these things is hard or time consuming and whichever ones you do often will make for fast turnarounds just due to experience.