If you watch movies enough times, regardless of how much you may enjoy them, you'll start to pick up on errors and mistakes. The Star Wars franchise is no exception, and one example of this is the Millennium Falcon. When Han Solo's beloved ship was introduced in A New Hope, it only had three landing gears, but three years later in The Empire Strikes Back, it had five landing gears. So when it came time to make Solo: A Star Wars Story, the crew decided to rectify this continuity issue through the Kessel Run sequence. Solo's visual effects supervisor, Rob Bedrow, explained:
So if you watch really carefully in the middle of the Kessel Run when we're coming up to that ice, that giant carbon berg Han does the slide on, we actually rip off the front two landing gears.
While the Millennium Falcon wasn't a new ship when it came into Lando Calrissian's possession, the suave gambler kept it in excellent condition. But successfully navigating through the Kessel Run is one of the hardest things a pilot can do in the Star Wars universe, and no ship is going to get out of there looking perfect. With Han Solo and Chewbacca at the helm, not only was the Millennium Flacon's front-facing escape pod ejected, but it also lost two of its landing gears during a maneuver to evade a pursuing TIE Fighter.
So there we have it. Canonically, the Millennium Falcon started out with five landing gears, and Han just didn't bother to replace them in the years between Solo: A Star Wars Story and A New Hope. But that changed leading up to The Empire Strikes Back, and James Clyne, Lucasfilm Design Supervisor, noted to ABC News that Han and Chewbacca made some adjustments to the ship during their time with the Rebellion. In Clyne's words:
Great, we'll break off two of the landing gears. We'll be down to three of the landing gears, back to our New Hope version. And we'll say well, in-between A New Hope and Empire, they had to add those two landing gears that Han busted off at some point between the two movies.
I guess Han and Chewie didn't see much need in installing more landing gears on the Millennium Falcon during their smuggling careers, but once they started going on missions as Rebels, they changed their minds. If you're fighting back against a tyrannical government, you might as well ensure that your ship can land properly. In any case, throwing in this little continuity resolution is a blip compare to everything else Solo: A Star Wars Story offered, but for the hardcore Star Wars fans, I imagine it's welcome.