Conventional rollers work just fine for some operations, but positioned incorrectly as table saw out-feed supports, they can push your workpiece to one side or another. A better option, ball bearing rollers allow smooth movement in any direction — so a misaligned out-feed support won’t skew the workpiece.
These rollers also excel on band saw out-feed tables, especially when you’re cutting curves in large pieces. Only ball bearing rollers will support the workpiece while allowing it to move in a curving motion.
If you like building your own work supports, you can get 5/8″ ball bearing rollers from woodworking stores such as Rockler or Woodcraft for about $3 apiece. If you don’t feel like building it yourself, pre-made ball bearing roller stands go for as little as $20.