Guidelines are magical.
Making changes is about resilience and being able to bounce back into your goals. Having a rigid structure can be too brittle and have the propensity to break.
Now. Everything has a time and a place. Sometimes it makes perfect sense to be on a really, really, strict program like the the Whole 30 so you can actually FEEL a drastic difference. Having a clear cut program in this scenario can be super beneficial.
Also. Willpower. It is a real thing and we have it in limited supply. If you can make something a habit - i.e. I NEVER EAT BREAD - then it doesn't have to play on your willpower stores and you can use that resource for a more challenging situation later on!
My point is that rigid has a time and place.
Always being rigid often (not always) leads to a bad time. A time of going into completely the opposite direction and then feeling like crap because you did.
They allow you to stay on the rails, but not so strictly on the rails it becomes painful, fragile, and breakable.
What I love is a simple card system.
Take an index card.
Add a grid to it.
Select what you'd like to keep track of - this could be things you either want or don't want to do.
For example: No Grains, No Dairy, or Meditate, Clean, etc.
You choose what makes sense for you. Give yourself a check or an X every time you do or don't do the thing. It is super lightweight - no need to log detailed calories, macro-nutrient ratios, weights, etc. (which all have their time and place) this just serves as an easy accountability system.
Will you have that cookie in the breakroom?
Then you wouldn't get a check on your card. Your choice.
This is a gentle hand to help keep you in check, but not overly consumed by structure.