Last year we spent 40 hours of printing to make a LOT of the green and blue rollers here:
https://twitter.com/frc2605/status/436627785478848512
We also found them to be incredibly useful for encoder and sensor mounting. Be sure to test specifically for each part. Tolerances will change from warp, and the warp will change from the part shape to the printer. The more you use 3D printing, the more you will come up with ways to use it, and what you use it for won't be a question anymore!