With the NHL trade deadline less than a week away, general managers around the league can learn a few lessons from the past.

Below, we analyze some of the biggest trades prior to the 2020 deadline to determine what worked, and what didn't.

Golden Knights improve goal prevention

The Golden Knights made two major splashes last year - both aimed at improving goal prevention.

On Feb. 19, they landed defenseman Alec Martinez from the Los Angeles Kings in exchange for a second-round pick in 2020 and 2021. On deadline day, Vegas acquired goaltender Robin Lehner from the Chicago Blackhawks for goaltender Malcolm Subban, defenseman Slava Demin, and a 2020 second-rounder. They also surrendered a 2020 fifth-round pick to the Toronto Maple Leafs for retaining a portion of Lehner's salary.

Martinez helped stabilize the Golden Knights' defense. He had an additional season left on his contract and is currently in the midst of a career year offensively.

Lehner became Vegas' primary goaltender for the postseason in 2020, sporting a .917 save percentage and 1.99 goals-against average in 16 games during the team's trip to the Western Conference Final. The pending UFA then signed a five-year, $25-million contract to stay in Sin City.

Vegas may not have won the Cup last year, but if they can go all the way this season, Martinez and Lehner will likely play big roles. Having both players for more than one year without giving up a first-rounder was a huge win for Vegas.

The lesson: Term/re-signability is ideal. This year's expansion draft complicates things, though.

Lightning go all in

The Lightning made a pair of key trades in the buildup to the 2020 deadline.

On Feb. 16 - eight days prior - they acquired forward Blake Coleman from the New Jersey Devils for a 2020 first-round pick and prospect Nolan Foote (a 2019 first-rounder). On deadline day, Tampa Bay stayed busy and landed forward Barclay Goodrow and a 2020 third-round pick from the San Jose Sharks for a 2020 first-rounder and AHLer Anthony Greco.