Over just the last six seasons, the Boston Celtics have made the Eastern Conference Finals an incredible four times, with this past season seeing them make it to the NBA Finals, where they lost in six games to the Warriors. Over this period, they've won 50-plus games three times, and it would have almost definitely been four times if not for shortened seasons. In addition, they've compiled an overall winning percentage of just under 62 percent and generally been very hard for teams to beat over this period.

So what have they had over this time that's made them so difficult to beat?

Most people would probably think the first thing is Jayson Tatum, but they didn't have him until the second season. It wasn't Brad Stevens either. Well, technically, it was, but he moved to general manager before this past season. Marcus Smart and Jaylen Brown were the only two constants on all these teams.

It was shocking when NBA reporter Shams Charania broke the news that the Celtics had offered the Nets Brown, Derrick White, and a draft pick for Kevin Durant. The Celtics' willingness to break up a young core that has already been so successful to take a chance on a player who turns 34 next season caught many by surprise. The Nets turned down the offer and asked not only for more draft picks but also Smart, the reigning Defensive Player of the Year.

While few, if any, would argue that Durant isn't significantly better than both of these players, it does raise some questions about whether the Celtics would be better off doing this deal or not. The first issue is the window to win. With the current core of Brown, Tatum, and Smart, the Celtics might still have a 10-year championship window. Trading for Durant likely shortens that window to 2-4 seasons.

A Durant trade also makes their defense a lot worse. Boston gave up the fewest points this past season in large part due to the efforts of Brown and Smart. They both play with a ton of energy, speed, and hustle, which an elder Durant can't replicate.

There's also the issue of who plays what position because this would leave the Celtics overloaded with forwards and lacking guard depth, the only playable ones being Malcolm Brogdon and Payton Pritchard. The team would have Durant, Tatum, Horford, Grant Williams, and Danilo Gallinari as forwards. So with Tatum, Horford, and Robert Williams as the current frontcourt, either Tatum or Durant would have to play out of position at shooting guard.

However, there are a few positives to the deal.

Durant makes them better offensively. Last season, he averaged 29.9 points and a career-high 6.4 assists per game. He shot 56.8 percent on two-point shots, 38.3 percent on threes, and a staggering 91 percent on free throws, making him one of the most efficient players in the league on an incredible volume.

The Celtics will now need to decide whether the shortened window and decline in their defense is worth the boost to their offense. They'll also likely be locked into this core as they've already traded a few firsts for guys like Horford, White, and Brogdon. The Nets are asking for a lot of draft capital here, so they won't exactly be flush with assets to change up the core if it doesn't work. It will be necessary for the Celtics to make sure they still have enough to win after trading for Durant, and I'm not sure that they do if they agree to the Nets' high asking price. Coupled with the fact that they'll have to include the last of their draft picks, I think trading Brown and Smart for Durant is too much.

I don't think Durant is a good fit with the Celtics as he and Tatum are similar players with similar strengths and weaknesses. The Celtics have a nearly decade-long window with these guys and can continue trying to surround them with the right role players or spend a few years stockpiling assets to get them a third star who doesn't cost as much as Durant. For those reasons, I would tell the Nets to knock somewhere else.