....
If your lathe is big enough for even a small Adjust Tru...and you need a
3 or 6 jaw chuck that is dead nuts..yes..they are indeed very handy to
have. Ive got {2} 6" ones and a couple 8" ones...and one 10" one..and
they have saved my bacon on more than one occasion .

But most people, for rough turning, really dont need one. They are very
handy for returning Stuff that has been turned before.

Gunner

Like Don and Gunner, I too have an adjust true three jaw. I set mine up once
years ago and don't touch it. Really close for most work. It should be
noted, I could have done nearly as well by boring my hard jaws. Scott Logan
of Logan lathes has a great write up on his web site for this task.

But, when I need dead nuts...

Soft jaws are the way to go.

Soft jaw in a lathe is something you have to do a few times. Once you're
past the learning curve, you can quickly bore a shave off your softjaw and
then insert your work and its absolutely dead nuts on. When you need to turn
a part from both ends and have the same diameter meet in the middle, this is
the best way to go.

Karl