It depends on how you are feeling and what you want to do. I have done a 72hr fast once a week for about 4-5 months straight and with using snake juice it was fine. You can run two 72 hour fasts back to back and use the 7th day as an OMAD or cheat day. Just depends on how you feel doing it. Only wrong answer with fasting is if you push yourself too much from my perspective at least
I’d limit a 72 hour fast to once per month. I am presently doing 4:3 ADF and like how I feel. It took a little while to get over the hunger at 24 hours without food, but I now do 40-42 fasts without feeling really hungry.
Weekly seems fine to me. I did a 48-72 hour fast weekly for 6 weeks then a 10 day fast. Every two months for a year for health reasons. Everything totally resolved. 40 years later i am getting back into it to reduce cholesterol.