I believe the biggest challenge for most people ( me included), is to consistently keep using the planners. You often can do " why bother planning for this when I will remember it ? " or "keeping everything organized takes time, why should I do it ? ", can eat away your motivation.
It's of course up to personality and self discipline, which can take time to develop, it is however, in long term, extremely powerful tool to use planners as you described.
I don't use a paper planner, everything is on a digital calendar and sends me an email reminder ahead of time (and phone reminders, too, if I want them). This way, too, my husband knows when I have something coming up, as I gave him access to my calendar. I have access to his, too, so it helps me with my planning.