Maybe in the old days with weak alternators and acid batteries, but high RPMS while winching in this day and age? Not necessary. Now if you are talking about extended idle times, then yes, bump your idle up a bit to keep everything from fouling, but even then, it should idle just fine for hours on end, and supply plenty of charge to keep the batteries up for winching 200 lbs or so indefinitely...
04' Rubi, with all the gizmos we need for long range excursions, / home modified excursion trailer;
96' Lexus 450, locked, loaded and ready to roll..
'12 VW New Beetle