I used to take speed daily - days on end, then crash for a few days, then days awake, then crash, then I pushed it a bit too hard (a few days after the Shadow people arrived) ended up in hospital and thought I was going to get sanctioned. I would get really really nice base (heart leaping out of your chest / helicopter in your ears / zooming in and out of what you were looking at). Clubbing my mate would do 10£ bags - people would dab it, I would bomb it all.
All the years I was full on partying I kept drugs to a weekend thing, I used to smoke hash like a trouper the rest of the time but nothing else.
I started partying on acid in 90-91, maybe a bit of speed and carried on like that as the local scene and sound system kicked off, I was a bit snobby about E back then. I found acid was becoming a problem when out and I wasn't enjoying it, so I switched to just speed for a while.
I tried a few pills but was a bit underwhelmed, then snowballs arrived and my life changed and I doubt I ever went out again with out doing E but still did a bit of speed with it but never a great amount.
Over the years my E intake increased but it never really seemed problematic and I was never one to take stupid amounts, it was all about the dancing for me not lying about on the floor with my eyes in the back of my head, but each to their own. I never got the same thing out of E without the right setting, music and dancing like a loon, it was the synergy of these things that I really got into.
I really slowed down on the partying around 2000 for a lot of reasons, it's been in the aftermath of that that problems emerged and what I would class as abuse started, for a long time I couldn't come to terms with life without partying,. nothing seemed to compare or provide the same release and feelings of deep happiness, this along side work stress and starting a family took it's toll.
I started using stimulants for days on end, mostly coke to begin with but then other stuff like Meph and PV and drink a lot, it all fell to bits a few years ago but that is a long and relatively mundane story.
I suspect the 8 years of weekly stim use and maybe by AD medication or brain chemistry has left me with a decent tolerance to stims, I can only judge this by others reaction to the same quantity of the same drugs but IME we are all different, I had friends who would take obscene quantities of pills, even at the peak or my usage it would be 5-6 pills ( real ones !) over 12hours or more I knew people that regularly did 20 or more, most looked awful on it but one good friend absolutely loved getting into that state and always had a great time.
I only really do speed these days (occasionally K) and then only every 2-3 weeks, I seem to have a decent amount of control over using it and like I said I find it doesn't leave me feeling that bad. Occasionally it spills over into the week but I'll just bump a bit in the day to keep me going, I can be productive on speed and it doesn't sketch me out.
I deliberately don't have many contacts for drugs, online is easier and means I can control the amount I get in, so when its gone its gone, I can see how low doses could be beneficial for depression and part of the attraction for me is that is relieves some symptoms especially fatigue and bypasses insomnia but I can also see that prolonged use would drive me back towards the de realisation and delusional state I got myself into before.