John Longmire has backed the Sydney Swans' youth to step up this year after they were stripped of experienced depth over the past two years.

The Swans' list has been in transition over the last couple of years, with a number of mature players squeezed out under a tightening salary cap and restrictions put in place on the club over the trade period.

Players Nick Malceski (Gold Coast) and Shane Mumford (GWS) have been joined in the Swans' departures lounge by Tim Membrey (St Kilda), Andrejs Everitt (Carlton), Jed Lamb (GWS) and Jesse White (Collingwood). 

After being ranked in the AFL's top two for both average age and games played in the past two years, the Swans now rank fifth in both categories.

Their average age is now 24.64, with an average games tally of 78.84, at a time when their premiership rivals are loading up on mature bodies.

Longmire, who is entering his fifth year as coach, said depth was "critical" to a premiership campaign, but he was not concerned about the prospect of calling on his young players to fill that role this season. 

"We've got plenty that can play a lot of league football and we're really confident in the younger generation coming through," Longmire told AFL.com.au.

"We've got 30-odd players who have played senior football on our list and we know players like Jake Lloyd, Harry Cunningham and Dean Towers can come through and play pretty big roles.

"There's always questions about how many you've got coming through, for any team, (but) we're really keen to keep promoting the fact that we've got some good young kids."

In 2013, the Swans had the oldest list, with an average age of 24.86, and the second-most experienced group, having played an average of 85.82 games.

They remained top two in each category last year (average age 24.78, average games 81.47) but dropped steeply ahead of this season, making them the only top-eight team from 2014 to lose experience.

Fellow preliminary finalists Port Adelaide, North Melbourne and Hawthorn all added age and games experience to their lists, while Fremantle remains the oldest list in the competition.

Age and experience aside, Longmire, who led the Swans to their 2012 premiership, said he took a lot of lessons out of last year's 63-point loss to Hawthorn in the decider.

"The first is how good the opposition was – they're fierce competitors and you can't help but have admiration for how they go about their business," he said.

"The second [lesson] is to make sure you play at your best all the time.

"While we won the most amount of games we have in our club's history, and we played some wonderful football through the course of the year, we didn't play as well as we expected on Grand Final day.

"You need to bring your best every time, especially against the best. That's the thing you look back on."

The Swans will pave their own path this year, not opting to mimic the Hawks or Port Adelaide, who shape as a trendsetter in 2015 with their attacking style.

"You need to understand you have the strengths of your own team and you need to make sure you coach to that as well, and understand that intimately," he said.

"The best teams are the ones that consistently do that on a weekly basis.

"They play to their team's strengths and that's ultimately what dictates how a particular club plays the game."