Hi Pat
If you've had it a few years you probably only have the original Wii Fit disc rather than the Wii Fit Plus they sell it with now. I have to say I probably wouldn't be using it so much if I only had the original. The two big differences (as I understand it) are:
Extra Games and Exercises
I believe the 15 games in 'Training Plus' are all new, and these are generally much more fun and 'game' like than the original balance games. The flying chicken game is an excellent spectator sport (watching the player rather than the screen), the obstacle course is highly addictive and a good way to burn a lot of energy and the snowball fight is a somewhat more morally acceptable take on the idea of a irst person shooter for anyone who doesn't like the idea of their kids slaughtering hundreds of people with a virtual Uzi. There are also a few new yoga poses and muscle exercises.
My Routine
You can put together a bunch of the yoga and muscle exercises into a personalised routine lasting up to 60 minutes. The downside is you don't get scores or to vary the reps. The upside is you get a much more continuous workout without being told incessantly to practise your yoga every day.
I should also point out (before Trey says anything) that I was referring to the female virtual trainer.