Reviving this thread because I am thinking about setting a schedule.
I figure if I book the next appointment while paying for my last one, I won't run into my usual issue where I put it off until I get enough photos taken of me and posted on facebook that I notice how bad it is looking...then nebulous scheduling makes it take even longer. If I just fixed it in advance, I would plan for it and rarely have a conflict (and now that I have a smartphone with integrated calendar, there are no excuses).
So when should I set it...5 weeks or so? I don't keep it really short so it has groom to grow between cuts before it looks terrible