Deciding to move up a level in training.

I recently received a question in our Facebook group about an athlete trying to decide if they should move up a level in their marathon training. There are a few things to consider here, but mainly, if you are continuing to see improvement with the marathon training plan you are using, it might not make sense to make a big jump. The second part of that was in regards to starting a more advanced plan, but giving themselves an out if they felt like it was too much. While the logic may be sound, the reality is that it might already be too late by the time that decision is made. My full thoughts on both parts.