Can anyone advise me on when I should shut off Traction Control?

When it's interfering with your driving, or you just want to do some burnouts.

Or when you're on the track.

There's no wrong answer.
I only turn it off when I need traction in the snow (ironically). I used to have Kumho "all-seasons" that sucked in snow, so getting up my snow covered driveway was a chore. I don't like TC kicking in when I'm trying to do it my way (it just slows you down).
Even with it "off" though, it still is working--but to a lesser degree.

Other than that, it stays on all the time.

PS- TCS and Stability can be disabled by holding the TCS button for eight seconds. I leave stability on all the time though because it practically saved my life once.

I leave stability on all the time though because it practically saved my life once.

Me too, that freaked me out.....

I wish that "OFF" was the default. It is the first button I hit after starting the engine. Unless it is very wet pavement, call me old school, I want complete control of the car. I have been driving a long time and if I do say so myself I am very, very good at it.
Joe P

When should you shut it off?

Immediately after starting the car.

Funny you guys mention that because I made it a habit when I used to drive an SVT Stang. I'm not one for show-boating or accelerating fast when it's not necessary, but I always turned it off anyways. Friends would always ask me, "why do you do that?" I never really had an answer for that.
I don't find it worthwhile in the STS.. it's AWD anyways.

I'll wager I've driven more miles on snow and ice over two lane mountain roads than nearly anyone else on this forum and I've never seen the need to turn it off. It works great just as it's designed to do.