I ferment up at least one batch a year.
I try to do a couple, but I had a batch go bad last year. Summertime.
The very best results are right about now, when the apples are fresh off the trees.
My problem now is if I start a batch, I might not have the room, I just mid-Aug bottled a run of Stout that is aging. That also came out really, really good, but another month or so it will get much better!