For example, every night I get the question as I put him to bed "What are you doing now, Mummy?" and I answer "Dinner, telly, bed" and he will respond "So you're doing dinner, telly, bed?" and I answer "Yes dinner, telly, bed" and he will say "Dinner, telly, bed?" and I answer "Dinner, telly, bed". This will continue for about ten minutes which is usually the time it takes to settle it into his brain worry-free and which is usually the time it takes for me to slip up and add something like "Dinner, drink, telly, bed" which will utterly worry him and the whole process will have to start over again.
In the summer holidays last year I almost caused him to have a nervous breakdown. We had planned to go to the cinema which I had repeatedly told him that morning but by the time we got there the movie was sold out...so we went across to Pizza Hut which was packed...so we popped into bowling but they had no lines...by which time I had made far too many changes to THE PLAN that he just couldn't cope.
So I'm trying to change things by not telling him anything until about two seconds before we do it. This way I can get through the day without having to repeat myself and really talk to him, and he won't get worried that Mummy won't stick to The Plan.