Second, the larger shank allows you to use a larger diameter bit. The only place you are likely to see an increased price is in the router itself. Again, it depends on what you plan to do with it. In the interest of safety, you should always select the right bit for the job. Longer bits tend to generate more vibration and this vibration causes wear on your router and bit.
Vibrations also result in a less accurate cut.
Try to select a bit with the largest diameter shank possible. Using a pilot bit If you are using a pilot bit make sure the bearing rotates freely. A frozen bearing can burn the edge of your workpiece. There are two things to remember when using a pilot bit. First, don't push too hard or you risk denting softwoods with the bearing.