When I damaged my heel I was told to rest 4 monthsish and I did. Usually do 10-12 a year, peaked at 13, less when I first started in 2003. I think you were correctin that I just managed to pull them off. My last marathon saw me beat my previous pb which I set over six years ago (3.25.33). I still see the potential to beat that on the right run next year - Manchester, York, Killarney? Two more this year just to push up to 96 and then a better training schedule up to April.
Just entered them and got on with it. Only ever had one injury as a result of overworn shoes in the heel. If I needed to adapt my running in a marathon I did so, ie the pace. Some runs are a breeze to be honest and in others they have been pretty demanding. Where there have been difficulties it has nearly always been a result of a poor strategy on my part. I don't think there is a science to it, let your body do the talking and react to it.