I had a few months between March and August of really, really abusing e's and doing a lot of speed. My friends and boyfriend were all doing it at the same time too, so we used to bulk buy and went from doing one a night to about 12, sometimes several nights in a row. We used to get them really cheap, so it always worked out lower in cost to pill it than go out drinking.
Got a very large amount once with my boyfriend and decided to get fucked. Dunno about anyone else but when they're infront of me, I can't stop. Point is, after this big long night of abuse, and several "this is my last one"s, we were fucked until about 9 the next morning. After the worst comedown of our lives, and being bed ridden for several days, we got them out and counted them. Between us we'd took about 60, and we were both petrified that we'd done some real damage and were going to die.
Anyway, the abuse ended after that and from August onwards we've only really done about 6 a night, fortnightly or sometimes even once every few months.