I am in control of my drug use, and I think it varies for everyone. I currently have a psychedelic no more than once a month, and due to other factors that may increase in time. This has not always been the case though, when I began using MDMA it started off conservatively, then escalated to a frequency of twice a month for about a year and didn't realise at the time I was habitually abusing it.
I felt guilty about my use, as some people may identify with, and I put it as a priority over more important things such as uni. I stopped using MDMA about 18 months ago and pledged to be committed to university and finish my degree. I will finish my course and feel I could continue along with this use pattern for years without adverse effects.
I don't wish for this to sound like I blame MDMA in any way, because it was my own lack of prioritising which cause problems, rather than the drugs. My first MDMA experience was very profound and opened a door into many interesting and exciting areas of life and knowledge, and for that I am grateful. There is a honeymoon period with drug use, especially MDMA, and you journey through the initial obsessive phase to appreciate the experience more without the the need to push your limits with excessive chemical and polydrug use.