HolteYou mean for your final master export, or an intermediate footage conversions?
Generally videos in North America are viewed at either 24fps (23.976) or 30fps (29.97). Film and some modern TV broadcast are 24fps, and traditional TV broadcast has been 30fps. There isn't a quality difference, those are just the standard master frame rates. As a rule of thumb, as long as your frame rate conversions are divisible by whole numbers you won't lose quality. For instance if you shoot at 60fps, and edit at 60, you should export at 30fps. 60 divided by 30 is 2. It's a whole number. Whereas 60 divided by 24 is 2.5 which is not a whole number and an indicator that you will be dropping frames in your final export.
That was a bit of a tangent, but it's a good rule to keep in mind if you're shooting numerous different frame rates.
If you're just converting your footage before you edit, don't. It's 2014 and you don't need to do that anymore unless you're cutting in Avid.
Thanks, I just didn't really understand the reason. This helped out a lot.