Washer--
found it best to inspect the belt, any signs of wear or splitting, then it would be time for a new one....
check and clean all inlet filters....
and most times, best to open the machine up, remove the splash shield, and clean all areas of soap scum build up....sometimes you have to remove the perforated tub, I think there are only 6 bolts on a Norge design....a long brush that you can slide down between the tubs can be very effective also....clean underside of agitator and areas....
check the motor glides for wear, or lubrication.....
Dryer--
the main thing, lint..and cleaning it out from the whole vent system, from the filter on out....and underneath...a vacuum will help, but compressed air is better...
inspect the belt for wear or cracking.......
lubrication for the bearings/rollers
final touches would be a good car wax and buff on both machines....