Around here, leaf fall lasts all winter and into the spring. We have a lot of live oaks here, my favorite leaf mulch, and the tree is not deciduous, but it's also not an evergreen, rather it's semi-deciduous and it starts losing its leaves this time of year, but very, very slowly and picks up as winter goes on, maxing out in late winter/very early spring. What's funny is that it generally only loses between 25 - 50% of its crown.
Then you got the Southern Magnolia, which is also semi-deciduous, but it doesn't start losing its leaves until early spring and it's very strange, because it drops tons of leaves, but if you look up at the tree it seems to have a full crown of leaves -- it never seems to be deficient in the number of leaves
You definitely want to mulch those leaves up with a lawn mower.