Taking over a gram was never something I had ever intended to do prior to my one experience of doing so... I think it's a mistake which can easily be made by certain types of people, in certain circumstances, however. In my experience these ridiculous binges occur as a result of one, or a combination, of the following:
1) Redosing in a desperate, unsuccessful attempt to regain the initial feeling of the roll
2) Going too hard on the initial dose and being so fucked up that you are no longer aware that you are taking more (which is what happened to me).
3) Not 'thinking straight' while you are on top of the world and feel like nothing can possibly go wrong
4) Being a fiend, who has picked a terrible drug to fiend on
I think there is always a risk of losing control with this drug (for some people more than others), and the possibility of overdoing it is, of course, exponentially increased when someone is not well informed about ecstacy HR. Going into the night with a ceiling dose in mind is probably a great way to avoid going too far and suffering from nasty short term and/ or long-term side effects.
I would say 0.2-0.25 should be more than enough for most people, given they are taking enough time between doses.