I am an A&P/IA at a flight school. We generally don't re-pack the bearings on our (Cessna and Piper) wheels during the 100hr or annual inspections because we go through so many tires, and every time a tire is changed, the wheel halves are split, cleaned, and inspected, and the bearings are pulled, cleaned, inspected, and repacked. If we notice something during the inspection, like an oddly worn tire or a wheel that doesn't feel right when turning, we will pull, disassemble, and inspect.
If I was to do an annual inspection for a private owner, I would look at the overall flight time since the last annual, whether or not any of the tires had been changed since then, the overall condition of the wheels, if the aircraft is hangered or not, and then make a recommendation as to whether or not repacking the bearings was necessary.