Recently we were asked from a Fort Worth client if leaving tree leaves on your lawn is ok. The answer varies.
Live Oak leafs no, they are very slow to biodegrade. All other leafs the answer is yes, but they need to be mulched, with a mulching lawn mower. I would not mulch large piles of leaves. Instead pick them up and dispose of properly.
Do I leave grass clippings on my lawn or collect them?
Yes, grass clippings add nutrients back into the ground, holding moisture better. Also save space in the landfills. Overall leaving grass clippings on your lawn is good for the environment.