Health is an important factor for both, obviously. Health permitting, I think they will keep it up. This is all new and exciting for Devin as he is really making his mark as a legitimate star for the first time. He's developed a lethal signature move, that sudden burst forward and pull back dribble for a midrange J. He's hit HUGE shots in numerous games with that move, and it's indefensible given the need to protect for his drive.
For VC, it's about his legacy and winning and proving he can lead a team far beyond expectations. His motivation will remain high throughout the year, which has always been the most important variable in his performance.
No question Vince will be subject to fatigue this year. He hasn't exploded on drives nearly as much in the last 9 games as he did in the first 3 and preseason, and he reputedly went all out in training camp, which he hasn't always done. So all the tough early practices he organized, training camp, and preseason rigors may have already caught up with him somewhat. But if Frank manages his minutes well, as he's been doing, and especially gets him proper rest on back to backs, he should be fine.