Only if you reach the boundary will the boundary recede before you. And if you don't, if you confine your efforts, the boundary will shrink to accommodate itself to your efforts. And you can only expand your capacities by working to the very limit.
- Hugh Nibley
I think it's important to remember that rest is so important. But, hoarding the good things like love, compassion, enthusiasm, and (where appropriate in our training) effort doesn't take us to a better place - it, in fact, brings the darkness in and closer. In training, and in life, our goals should always be to expand our current capabilities. If we choose our training and life goals appropriately, and take time to restore our foundations on a regular basis, we rarely have to worry about overextending ourselves.