> why worry about something you can barely see or notice until it's already a problem?
So, you measure hair loss with the Norwood scale. You don't go from 100% hair to bald spots immediately.
First, you'll see diffuse thinning where the thickness of your hair drops significantly.
In the first stages of diffuse thinning, it won't be apparently to 99% of people that your hair is thinning but you'll immediately notice when you take a shower / apply shampoo (it's really obvious when your hair is wet).
I'd say that's when most men realize they're losing their hair and that's when they should get on Finasteride.