How often do you check you bearings?

Thanks for all of the input. Just to follow up, Neu recieved my 1512 on Tuesday afternoon and they put it in the mail back to me Wednesday afternoon. I also ordered a tube of 10 replacement bearings. The charges where $60 total. ($30 for the bearings/ $30 for repair and shipping) I would say that's pretty good all around. As far as how often the bearings need to be changed, they recommend replacement as soon as the bearings make any noise what so ever. I will start removing my motor every 5 packs from here on out.
Thanks again for your input.
Brian

[Shark413]

Here is the tool I was talking about.


Aluminum rod with a small cone on the end.


The bearing fits over the center nub and that helps center the bearing.


The green area is lower than the outer edge, so only the outer edge contacts the bearing (the tool only presses on the outer race).