Steve,
You're already strong. You can afford to mess around with light weights because you've already put in the work with heavy weights that has forever changed the trajectory of your physical capacity.
The vast majority of the posters here are not already strong. They have not been through that process. That's safe to say because it's true of the vast majority of people period - no matter how much time they've spent doing this-n-that in gyms. They, unlike you, cannot afford to be content to maintain movement patterns with light weights whether they realize it or not.
We lose strength and muscle as we age. It's a losing battle, but it's a battle that must be fought nonetheless. The battle begins in earnest around 45-50 years of age. It is much, much, much, much better to enter the battle with a bunch of extra ammo in the form of accumulated muscle, strong connective tissues, dense bones, and as much strength as Bill can convince you to build.
That is what the squat is for. Same with the deadlift (no, they're not the same), the press, bench press. These movements done correctly use the greatest muscle mass through the longest effective ranges of motion which allows a trainee to move the most weight thereby getting stronger in the most direct and efficient way possible. Loading them "heavy" and progressively overloading them with focused intensity for 6-9 months will quite literally change the structure of your body into something much more able to meet the relentless demands of aging.
Then you can do all the pattern maintaining you want.