Sorry you've not had any responses, it's annoying that this board is specifically for things like this but is quiet! Maybe Chat would be better?
Is it a PIP renewal? I don't know about ESA but for a PIP renewal I would give as much info and details as possible of any changes and as much supporting evidence as you can. If you have a fluctuating condition I don't like the advice "write everything as though it's your worst day" as I don't think it's helpful, the criteria for tasks is can you do things safely, to an acceptable standard, repeatedly and in a reasonable time, so I would refer to this as much as possible and give examples.
Please ignore if this is not relevant but if you are under various clinics/consultants ask to receive follow up letters of all visits/telephone calls as they are useful for supporting evidence and for you to refer back to. Basically for a PIP renewal, despite what DWP say, I would definitely not just say "refer to previous application" etc, I would (I know it's time consuming and depressing) basically write your original answers again and add as much information as you can if it's relevant, or taken place since your original award eg any operations..
Also if you are asked to attend am assessment, if it's not practical ask for a telephone appointment instead. I was called for an assessment 2.5 hrs travel away, I absolutely couldn't do that anyway, but I know if I had attended it would have been used to say I was "able to xxxx". I actually believe this is a deliberate tactic.
I'm afraid I don't know about ESA but there are more knowledgable posters like @babyroods (I hope you don't mind being linked! Please tell me if so) and Money Matters or chat topics may be helpful.
Good luck, it's a fucking nightmare I know!