Frankly, in my opinion, absolutely fucking none. Not any at all whatsoever. I can only imagine the addition of modafonil would further disrupt the sleep cycle that you do get, causing even more damage (even if it doesn't cause damage otherwise).You can use amphetamine and stay awake for 20 hours, then crash for 10 and do that... well, almost indefinitely. I did stretches of 3-4 days one to two times a week for years, and my health didn't actually begin degrading (it baselined at a lower-than-average level is what I mean) until I started just doing back-to-back runs nonstop 6 months ago. It really depends on the person's physiology, frankly. But again, in my opinion, the addition of modafonil would just make it worse. I don't see how it could protect you at all.