Not everyone should do psychedelics thats for sure. If you can't handle it or have no idea what to expect, it should be done with extreme caution or not at all.
But on the other hand, I have never had a sitter. Never needed one. Many differnt drugs, some times many different types at the same time. Salvia was the first true psychedelic i ever tried though. My first trip i just laughed and laughed. Literally rolling on the ground. By the 3rd or fourth trip, took about a month to get that far, i wasn't laughing anymore. I wasn't me anymore. I noticed that it was like a dream. I would experience the trip, remember it well, then over a short time start to forget details, much like a dream. This aspect of salvia went away for the most part though because after say the 20th or 30th trip I didnt really forget anymore. I could retain it for the most part, I would remember. But interestingly, after say months or maybe years of not doing it and then going back to smoke some, once I would take in the first hit I would get an instant flashback of memory. Lost memories of what it was truly like to be under the influence of it. And I would almost always think or say "THAAATTS right, now I remember" and then be off in the trip. And it felt like going home. Which to some might sound fucked up, seeing as how everyone i know hates the stuff. Calls it alien or hellish. To me its like going home to a place I had forgotten. Forgotten how wonderfully profound it was. Hard to explain. I havnt done it in over 5 years...why?
Always alone from the start though. Your alone in life and i belive when facing the end. Which i think psychedelics gives you a glimpse of. Some times though, while wandering alone in the dark, one can get lost. There is no help though, sitter or no sitter. If you wander too far off the path, I beleive only you can find your way back. Be ready to never be ready. So exciting!