[glend (Glen)]

Guess I am a Luddite, as I am against them. I went through a phase of putting a motor on my TS APO, and letting SGP do the work but I was unhappy with both the outcome and the cost. I am trying to simplify my setup not make it more complicated. I found that often the SGP focus was not that sharp, and that my Batinhov mask gave much sharper results. Motorised focusers also waste a fair amount of imaging time and are another thing that requires power, cable management, etc.
For my setup, where I have matched filters, which are parfocal, switching them on the wheel does not alter focus in the image file. I can start a run and come back a couple of hours later and the focus is still perfect. I rarely bother checking anymore.
But hey, give it a go, if you don't mind the hassle.

Two caveats to note: you must have an excellent imaging capable focuser on your scope, which will not slip, twist, etc; and your equipment must be at equilibrium (adequately temperature adjusted). Scopes with poor focusers would obviously benefit from SGP focus checking.