I wouldn't suggest alternating days because Effexor's half-life is so short that you're depriving your system on one day, then resupplying it the next -- a yo-yo effect, so the body doesn't know what to expect or how to adjust. In my opinion, going to a lower dose is more effective than alternating, and then giving your body time to adjust to that. As far as how long, I'd suggest giving it as much time as you've given your other decreased doses. Good for you for getting this far and good luck with the rest of your taper!!