Why should any trip be painful? Any pain is a choice, whether we know that or not. I think the basic rule is that if you trip on shrooms one night, you're going to have to do 2x that amount the second day to trip about the same. Seems about right in my experience. I wouldn't recommend tripping more than once a week unless you have a special reason to. (Festivals, friends going away, you're going to die the next day, etc.)