Many of us are on the email list of the BGU author (Griff). And recently one of his emails addressed the issue of practicing standing up. In it he stated that if one doesn't play standing up when one does it is going to be a "rude awakening".
And in a guitar magazine (I cant' remember which one) recently the author called practicing always while seated "bedroom syndrome".
Both of these reminded me just how bad I am about this. I rarely practice standing. Almost never even though I know that I should. In my defense it hurts to do so because of back issues. At least it did with my Les Paul or Strat. But I have recently purchased a semi-hollow body and a hollow body (Gibson 325) and my new PRS is really light. And even if I didn't have these I could have practiced for a few minutes of each session standing. So I no longer have any excuse.
So I have to do this. And the few times that I have it was a rude awakening.
But I am curious what others are doing. I know to jazz & classical players it's probably not as important. But do you play standing up? How much of the time?