Question about switching from 16 to 24 bit

Now that I've set Sonar to record using 24 bits, can I add new audio tracks to projects I started in 16 bit or should I keep my 16 and 24 bit projects separate?

Any other thoughts, opinions, or tips about recording 24 bit are welcome.

Thanks very much!
Sam

General 24 bit recording tip: you now have a lot more clean headroom, so take advantage of it. Recording with peaks around 10-12db is my rile of thumb. Some go lower, some higher, but you don't want to be *anywhere* near the red. Also apply this to your mix process, and voila, clearer , punchier mixes will result for almost no effort.