Yeah I'm 33. I actually still trip pretty often compared to most people, pretty heavy drug user in general, but I've always had a semi-superhuman constitution for drugs. Even so, DOC is a bit much for frequent use anymore. Generally these days I use low functional doses (within a few milligrams) of 3-MeO-PCP pretty often and about once every 2 weeks on average I take a psychedelic (though sometimes, like a music festival or an especially awesome and eventful weekend, I'll take them more often or even multiple days in a row), either a lysergamide or a tryptamine, and when I have empathogens I tend to use them pretty frequently (which is my worst drug habit anymore, but I only allow myself to obtain them infrequently). The tryptamines in particular are great because I can dose high with literally no mental or physical cost... I come out of it feeling better than before I took it, sleep is no problem, and it's a highly satisfying experience. Lyseragmides give me a similar sort of experience as DOC but there is less energy drain that happens and they don't fuck with my sleep nearly as much.
But, DOC is also a highly satisfying experience, so I always come back to it from time to time.
Fortunately I obtained a lifetime supply, I can imagine using it for many years to come but I'm sure there will reach a point where I can't take it anymore, an earlier point than for other psychedelics.
In my twenties it was like, no holds barred, I was always able to do well at work and function in life but I took a ton of drugs at a totally inappropriate rate, but fortunately it was mostly psychedelics (and opiates for a long time - and weed, tons of weed), never got into the really damaging drugs much, and I've never IVed and I never will. I feel pretty unscathed by it. I guess psychedelics agree with my brain, I've never even gotten a touch of HPPD despite periods of time where I was tripping almost every day, or literally every day for weeks. I actually feel like I'm at my peak of mental and physical performance at this age as well as my overall happiness and state of mind. I've never had a bad trip either, I had one (my third trip ever, a long time ago) where the trip was horrible to experience but I actually felt euphoric for days once it came down because I was so happy to be normal again, and I learned a lot. I consider myself extremely lucky and possibly some sort of freak.
So don't do what I did, I'm rather surprised I'm not crazy or a vegetable right now because of some past years, most notably 2006-2008.