I think there are two different scenarios. As Ken mentioned moving your machine or transporting it in a vehicle and stationary use.
The weight on the shaft from the stone will over time damage the bearing surface albeit slowly as the vehicle hits bumps. It would be interesting to critically examine the bearings of a Tormek that is used in a mobile sharpening setup with the wheel never removed. I too tend to remove the wheel and install the spacer if I need to move it any distance. My bench has wheels so this does not come up too often.
After each use I don't think it is necessary to remove the wheel. It is important not to leave it sit in the water. I think many of us that use multiple wheels may take the last used wheel off when done. When I do this I often leave the SG-250 off until the next session. With old machines the shaft also tended to rust over time making it a good practice to remove the wheel and dry the shaft.
The weight on the shaft from the stone will over time damage the bearing surface albeit slowly as the vehicle hits bumps. It would be interesting to critically examine the bearings of a Tormek that is used in a mobile sharpening setup with the wheel never removed. I too tend to remove the wheel and install the spacer if I need to move it any distance. My bench has wheels so this does not come up too often.
After each use I don't think it is necessary to remove the wheel. It is important not to leave it sit in the water. I think many of us that use multiple wheels may take the last used wheel off when done. When I do this I often leave the SG-250 off until the next session. With old machines the shaft also tended to rust over time making it a good practice to remove the wheel and dry the shaft.