Yeah, the "doesn't carry the sleep debt" bit is dubious at best. Maybe not at much. But it doesn't fit my experience at all. Anecdotes not being data, and all that, but for me at least I still wear down over time with a couple of uses of modafinil a week unless I actually make sure to catch up on sleep, to the point where I am careful to limit how often I use it, even though it is far easier to avoid totally crashing with than caffeine and generally feels less stressful on the body (whether that feeling reflects reality, I don't know).

Well I think you're talking about something different. From what I've heard (and in my experience), I can skip a full night of sleep with Modafinil and then fall back into my normal sleep schedule the day after.

You'll probably fall asleep earlier in the day, but you'll only sleep for 8 hours. This is why it's useful for offsetting your rhythm.

Ritalin/Adderall is very different. If you use it to stay up for 8 hours, you'll sleep for 16 hours the next time you pass out.

Again, though, the data is ambiguous AFAIK.

>Ritalin/Adderall is very different. If you use it to stay up for 8 hours, you'll sleep for 16 hours the next time you pass out.

From my subjective experience, this isn't necessarily true. All-nighters with modafinil vs. all-nighters with adderall require the same amount of catch-up sleep for me. Modafinil just gives me a less jittery wakefulness.

If you fall asleep earlier in the day, you're paying offf your sleep "debt" right away. When I use it I go to bed at roughly normal bedtime the following night. At that point 8h sleep is certainly not enough. Though I'll usually not "catch up" more than 1-2 hours extra that night. If I want to I can push through and continue as normal, and even do multiple more cycles, but over time I do end up tired enough that I need to catch up with more sleep.

I tend to prefer to use it to offset sleep for relatively short periods - e.g. get an extra night of work, and then sleep a bit longer for the next couple of nights - as I feel it's more productive to get a longer block of time where I'm fully alert, and give up late evenings when I'd feel tired anyway to recover.