The two times I ate non keto for an extended time was when I was sick, and had a lot of nausea. Both times were about 3 to 5 day and I generally just ate pita bread w/ shredded cheese, microwaved. As soon as I knew I could go back to keto, I would plan one meal of something I missed. Was never as satisfied as I thought I would be.
The next day I would be right back on keto and never look back.
Other slips would happen when I ate out, usually with a sauce. I just go home and be keto, but on this diet, I never felt the need to beat myself up over it. Unlike other diets where I would fall off and stay off.
Keto forever.....unless I have the flu or a severe case of vertigo.