Depends what weed, how much and how often.

I wasted bout 4 years smoking almost everyday some shitty skunk I was getting from a local dealer in a shithole of a town when I was growing up.

Sure had “good” time but at the same time could have gotten good or better at some skills or sports, since I was talented and had sports potential.

In short, smoking hard shit everyday when 16, 17 ish kept my head hazy and thinking about how to get baked with friends.

I regret part of it for sure, since never realized the full potential I had.

For sure it depends on those 3 factors.