I eat from 12 - 6 everyday except Friday and Saturday. Those days I allow myself to eat from 12 - 8, so I can go out to eat with friends or family in the evening. Not really cheat days though as I’m still eating relatively healthy and counting calories.
On average, I flex to a shorter fast about once a month. I usually do dinner-only OMAD, but will occasionally do a shorter fast (like 16:8, 18:6, or 20:4) to accommodate a special occasion meal with friends and family. I don’t think of them as “cheat” days — just as shorter fasts.
IF has become the normal, natural way that I eat. I do it in a way that fits my life and feels natural. It’s not a stressful, artificial restriction that I mentally need a break from.
I’m also not restricting what I eat — if I want to have pizza or burgers and a beer in my eating window, I do. So I don’t need a break from strict diet food.
I guess what I’m saying is, it has worked best for me to do IF gently enough that I don’t need or want breaks or cheat days from it.
I do 18:6 pretty much everyday and leave my off days to special occasions or when I go to someone’s house for a meal. I say you do what feels right for you. I try not to do anything that would deter me from continuing IF.