NBA

One of the reason that so many people love college basketball more than the NBA is because they feel like all of the college guys play every game like it's their last. There is no coasting in college.

Well, I have a hard time believing not every game matters in the NBA too. That's why depth is such an issue and if you need to rest your "stars", you should be able to play elite level players behind them.

Now, take a look at this from NBA TrueHoop, and tell me, "Not every game matters"

It was a February 3 game against the Nuggets. Chris Tomasson of INDenverTimes remembers it well:
The Spurs J.V. team battled well. But they fell 104-96 to assure that Denver won the season series 2-1.

Well, guess what? The Spurs and the Nuggets both finished the season 54-28, with Denver, due to the tiebreaker, getting the No. 2 seed in the West and San Antonio settling for No. 3.
Had Popovich used his top players that night and the Spurs won, San Antonio would be the No. 2 seed and would be in line for homecourt advantage for the first two rounds of the playoffs.
Of course, an extra loss would have meant the Nuggets would have finished the season 53-29. That would have resulted in them losing the Northwest Division to Portland (54-28) and losing a tiebreaker to Houston (53-29) for the No. 4 seed.

So, if Popovich had used his top players that night and the Spurs won, the Nuggets now would be the No. 5 seed instead of having homecourt advantage to start the postseason for the first time since 1988.

Hypotheticals can drive you crazy. And who's to say the extra wear and tear wouldn't have cost the Spurs another game or two somewhere down the line.
To me the point is, more than anything: It's a very close contest, and every little decision has the potential to matter.