Free spinning isn't a measure of bearing wear, it is a measure of how much grease is still in the bearing.

Whenever I get a car with over 100 K, I lube alternator / idler / AC bearings if they still feel smooth. Don't fully pack the bearing as this creates excessive friction and can burn the grease leading to a bearing failure. Something like 50 % fill is plenty with less grease used if the bearing sees high speeds. To some extent excessive grease will be expelled from the bearing during use so fill volume isn't hyper critical.

About 8 years ago I got a 99 Blazer with 125 K miles for Dad to drive. I lubed all of the bearings and it now has 230 K on the original idlers / AC bearing. The alternator and water pump were replaced due to non bearing related failures.