Two of the best, Anthony Calvillo of the Montreal Alouettes and Henry Burris of the Hamilton Tiger-Cats, are 40 and 38 respectively heading into the 2013 season.
The 39-year-old Kerry Joseph, who began his career with the defunct Ottawa Renegades, is hanging on as a back-up with the Edmonton Eskimos.
But neither Calvillo nor Burris looks to be slowing down.
"Anthony is in phenomenal shape for his age," Montreal general manager Jim Popp said. "He's playing at the highest level, MVP level.
"So we don't really look at his age. When the day comes that he says 'I'm retiring, I just can't do any more on the field,' then it becomes more of a panic button scenario."
There was speculation last winter that Calvillo may pack it in when Marc Trestman left after five years to become head coach of the NFL Chicago Bears, but Calvillo was back in camp under new coach Dan Hawkins.
And why not? He completed 333 passes to reach the 5,000-yard mark for the seventh time in his career in 2012, despite playing through an injury to his left (non-throwing) shoulder that hindered his throwing motion and required off-season surgery.
Two seasons ago, the East Los Angeles native broke a handful of passing records set by Damon Allen, who played until he was 44.
Calvillo enters his 20th CFL season, his 16th with Montreal, with 5,777 completions for 78,494 yards and 449 touchdowns.
If he stays healthy, he should top 10,000 pass attempts, 6,000 completions and 80,000 yards this season.
If he doesn't stay upright, Montreal could be in big trouble. His backup in recent years, Adrian McPherson, is gone, and he will have third-stringer Josh Neiswander and rookie Tanner Marsh as contingency plans.
"We're always preparing people," said Popp. "The truth is you don't know what you have until you have to play someone else and see how they perform."
Burris is also coming off a year that saw him establish career highs in completions (391), attempts (604), yards (5,367) and TDs (43) for the Ticats, who otherwise were a bust at 6-12 despite a league-leading offence. Burris has thrown for over 4,000 yards in eight of the last nine years.
Bringing in the experienced Kent Austin as head coach may be what Hamilton needs to get a talented group to succeed on the field and keep Burris at his top level in his 15th CFL campaign.
"He had a really good camp, he really did," Austin said. "He came in in great shape, he was stronger than last year from what I understand.
"He threw the ball pretty well most of camp. He's really smart, he takes coaching, he wants to be good and wants to win."
Not only did Austin win Grey Cups as a player, he's also excelled with veteran quarterbacks as a coach. He was the Toronto Argonauts offensive co-ordinator in '04 when Allen was a Grey Cup champion and CFL MVP and was the Saskatchewan Roughriders head coach in '07 when Joseph earned the same double achievement.
"He's brought success to quarterbacks and also brought success to his teams," Burris said. "He's a great coach and both Damon and Kerry have told me I'm going to enjoy working with him."
Burris, acquired in a 2012 trade from Calgary, is backed up by the returning Dan LeFevour and by Jeremiah Masoli.
Nearly every CFL team can kiss its championship hopes goodbye if its starting quarterback has a serious injury. Except Calgary.
The Stampeders didn't miss a beat last season when Drew Tate dislocated a shoulder in the second game of the 2012 season. Veteran Kevin Glenn stepped in and went 10-5, putting up 4,220 passing yards with a career-best 66.7 completion percentage.
When Tate was hurt again in the playoffs, Glenn took them to the Grey Cup game.
Both are back, along with impressive third-stringer Bo Levi Mitchell.
The poster boy for quarterback injuries in Winnipeg's Buck Pierce, who has started only 28 of 54 games in the last three seasons.
When he's healthy, Pierce's battling style produces more wins than losses, like in 2011 when he played 16 games and got the Blue Bombers to the Grey Cup game. But last year he played three, sat out eight with a knee injury, came back to beat Hamilton, then got hurt again.
His back-ups from last year, Joey Elliott and Alex Brink, are gone, so Justin Goltz is the new No. 2. Goltz played three games last season.
The heat will be on Ricky Ray to lead Toronto to a second Grey Cup after a phenomenal first season in double blue following his move from Edmonton.
The 33-year-old threw for 4,069 yards in 14 starts last season, and was more impressive in the post-season as he outduelled Calvillo in the East final and then took his third career Grey Cup.
With veteran Jarious Jackson gone, Ray is backed by Trevor Harris and Zack Collaros.
In Saskatchewan, 30-year-old Darian Durant returns for an eighth season after a so-so 2012 campaign by his standards. He started 16 games and threw for 3,878 yards and 20 TDs.
The Roughriders have a promising back-up in Drew Willy, who started twice and completed 69 of 95 passes for 709 yards and five TDs.
In Vancouver, Travis Lulay's performances dipped a tad from 2011, when he was named outstanding player of both the regular season and the Grey Cup game. But he remains perhaps the league's most dangerous double threat to pass or run the ball.
His back-ups include Elliott and Thomas DeMarco, because last year's much-coveted No. 2, Mike Reilly, is now an Edmonton Eskimo.
Reilly was in a lively battle for the starting job in Edmonton when his rival Matt Nichol suffered a season-ending knee injury in the pre-season. Now, after three years as a back-up in B.C., the 28-year-old will get his chance to be a full-time starter.
He completed 52 passes for 682 yards and four TDs last season for the Lions.