22 years, but for most of that, was an inconsistent weekend user and often went a few years in between uses. Now I'm a daily medical user (past 6 months). What I get out of it as a mature 40 year old is by FAR much more than I got out of it just messing around in my 20s with my friends.
If I respect the herb, it respects me back. I get out of my weed smoking whatever I bring to it. If I approach with a sense of sacredness, I receive sacred experiences, if I approach just to relieve pain, that's all I get.
Also, I learned that I need my sober times to integrate the stuff I've learned while high. If i'm not actually using it to improve my life, it's pointless.
Also, depending upon what strain I take and how much and my setting and intent... weed may as well be 1000+ different drugs. Most of the time I take it it's my "aspirin" (I'm a medical user) and I don't use a lot in one sitting with my weak, low-power vape, and I don't get very high. If I'm bored and use it to escape, I'll get minimal results from it, I'll just feel more bored and like I wasted my time. If I decide to actually smoke a bowl and use it as a sacred herb and have realizations/visions... I can do that, too, by putting myself into a trance with meditation beforehand and doing some form of ceremony before I start smoking. It may as well be 1000 different drugs. What chemicals are already in my brain affect what I am going to get out of the weed.
Also: ALWAYS choose to use legally if you at all can help it. If you have access to medical marijuana in your state and have a qualifying condition - take advantage of that. Yes, there are up front fees, and dispensary weed is more expensive, but it's a lot cheaper than lawyer fees and fines and or jail time. And not having worries about doing something illegal will make the experience better. It's easier to approach the herb with respect when you don't feel like you're doing something naughty.
No interest in other drugs nor have I ever done any other drugs... weed gets me where I want to go. If you're thinking of trying something else, try different weed first...