The school of thought is that teams would be working on resting their starters and top 6 players this season to make up for the fact that the schedule is so hectic. The Celtics have even more incentive given their age. So how are coaches doing? Hardwood Paraoxysm ran the numbers and the results aren't good. Most teams are actually playing their top 6 players more.
NBA Mythbusting: Are Coaches Resting Their Players More This Year? | Hardwood Paroxysm
As the season progresses and the trade deadline passes, it’s perfectly reasonable to anticipate this year’s rate regressing to last year’s. However, the takeaway here is that, at the very least, coaches are not resting their starters/top six players any more than they did last year. Be it due to injury or the night-in, night-out pressure to win and stay off the hot seat, the distribution of minutes so far this season is actually more compact than last year. When your favorite Blazers or Bulls fan complains about their coach not pulling the starters in a blowout, they’re not just blowing smoke. It’s a league-wide trend.
The Celtics actually are one of the exceptions. Doc is playing his top 6 about 4% less. So at least he's trying.