It’s been said that you shouldn’t fix that which isn’t broken. There is no shortage of instances of that in the NBA throughout history.

Fair. On the other hand, isn’t improvement a noble goal? The wheel didn’t necessarily need improvement, but the car sure is a better mode of transportation. 

NBA teams sometimes need to find the same balance. You may have one of the best teams in the NBA. Messing with its chemistry isn’t always ideal.

At the same time, if the right opportunity comes along, you may look to improve it. 

For example, look at the Milwaukee Bucks. They could keep this exact roster all year, and nobody would bat an eye. They’d still be in the running for the NBA championship. 

At the same time, they could try to make a major improvement. Here’s a deal that has them doing so by acquiring DeMar DeRozan of the Chicago Bulls.