I used to plan a lot more than I do now, so it might be something that becomes less with age and experience. 10 years ago I was obsessed with food and cooking and would plan meals for a week in advance, down to the calorie. Any events happening within the week would have to be planned for and meals planned around them. I would also have a routine on getting home from work and a fixed set bedtime, which I enforced for my (ex)husband on the basis that I needed to sleep at that time and couldn't do so if he was still up elsewhere in the house. If things didn't go to plan I would become very upset, but luckily this happened infrequently.
Since living alone I have become more flexible, although I have also been more emotionally unstable (and have poor sleep and eating patterns - tried to get back into obsessional organising again, but it doesn't work anymore). Organising everything does have advantages and I have been praised for my (self) organisational and time keeping skills. Certainly is a very useful skill in my job. My response was always that I had to be organised otherwise things would become too stressful for me - it is stress avoidance because I don't deal well with stress. But I really can't understand people who are constantly disorganised - I don't know how they can live with such chaos, I would lose my touch on reality and become psychotic.
Nowadays I do have plans a long time in advance, but they tend to be plans I have made with other people (and most of my friends, although NTs, are also busy people and like to plan, although not obsessively). I don't plan meals very much anymore and I can do things last minute if I don't have any definite plans and I feel like it, whereas before even a night in not doing anything much would be a definite plan and I would miss out on things (and feel really bad about missing out) in order to keep to the plan (because I'd feel worse if I didn't).
I have a sort of visual calender in my head (not dates, but all the weeks, months etc. marked on), and automatically put new and potential events onto it when I learn about them, so I can literally see ahead in time. I often stick other people's events onto my mental calender too and end up reminding them about things they've forgotten about.