You have been taking modafinil for years now and pretty heavily.
I actually haven't. The last of the checklists in the post is actually the one I take the most seriously. I did use modafinil heavily when I was originally prescribed it (for sleep apnea) but now treat that with a CPAP machine instead. I use modafinil occasionally as needed(/wanted).
How have you dealt with tolerance?
I actually have a lot less tolerance for the stuff now than I did when I first started. Even at a third of the daily dose I orginally took I now don't feel tired much for several days. (I can only speculate about why.)
By taking more or cycling usage?
I cycle. Not because it doesn't work but because I need to ensure I get adequate sleep to keep up with the recovery demands of my exercise regimen without weakening my immune system and taking on the features of a zombie. (Bloodshot eyes, pale face. The look people get when they aren't sleeping enough.) I don't like taking modafinil more than once or twice a fortnight.
Checklists are powerful, and I don't use them enough. You probably don't, either.
Below are some of my own checklists. Please share your own!
I don't know how to do X.
I don't understand X.
I feel mentally exhausted but can't afford to sleep right now.
I don't want to get out of bed, but I should.
I'm procrastinating on task X.
I'm about to send an email / post a comment of some significance.
(I don't do these ones nearly enough! D'oh!)
I feel sad about not doing a better job at X.
I'm about to make a decision of some significance.
I could go on, but... what are yours? (Now is also a good opportunity to make some checklists for yourself, based on what you think tends to work for you.)