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.
RE: Short Term and Long Term Planners