I pull out my hunting rifle in the couple weeks before the season to re-acquaint myself with the trigger.
I didn't use snap caps for several years and there was no loss of function. I use a spent cartridge nowadays, but small scale dryfiring should be okay until you can use something with some resistance.
I wouldn't do that with a rimfire rifle. I don't have a 10/22, but if the manual of that says it's okay, then go for it with a 10/22
I'm right about the metric system 3/4 of the time.