The Hoops boss has already consigned to the history books 2013-14, which yielded his fifth trophy in charge and the league championship for a third time.
This will be more important to those who did not take the opportunities presented to them over the course of the 53 games, but who are desperate to be given a second chance - including Derk Boerrigter, Amido Balde and Teemu Pukki.
But it also a wake-up call to the players who believe they are secure as first-picks in Lennon's side, because the manager does not want anyone to let their standards drop through moving into the comfort zone.
"A lot of players will be pretty pleased with the way they played this season," said Lennon. "A few will be disappointed. But this season has gone now, It's finished, and the slate will be wiped clean for when they come back in June."
Lennon's focus has switched to defending the title and strengthening the squad to be more competitive in Europe.
Celtic are already established as prohibitively-short odds-on favourites to make it four-in-a-row, which Lennon recognises presents the danger of complacency.
The manager successfully stopped that at the door this season as the 99 points collected - his best total in his four seasons in charge - confirms.
But how tough will it be to keep what will be ostensibly the same squad as focused for another 38-game campaign?
Lennon is confident he can, explaining: "They have got a great mentality and a great attitude. They know what is required."
While the level of competition from the rest of the Premiership is unlikely to be any higher than what faced the Hoops over the past 10 months - they finished 29 points clear of second-placed Motherwell - it is competition from within the squad which Lennon believes can keep everyone up to the mark.
Even before any new faces are brought in, he is confident that, with Nir Biton and James Forrest back after the injuries which ended their season prematurely, the battle for starting places will increase.
And he has flung open the door to rising stars like Filip Twardzik to stake their claim for a place. Liam Henderson did that to great effect in the second half of this campaign, and the Hoops boss said: "There are opportunities here. I am pretty happy with the majority of the squad, but I still like to think some of them can improve.
"We see something in them. But, at a club like this, you can't wait forever for them to find form."
Lennon added: "It has given us a lot of encouragement in the second half of the season to see so many players coming in and playing so well.
"It will be nice to get a couple of additions, if we can, and add a bit more quality as that gives the rest of the team a lift."