Lycoming/clones with fuel injection, you typically only mess with mixture when starting and stoping them.
There is of course a minority religious sect within GA who follow lean-of-peak theory and mess with their mixture constantly for better mileage (and possibly better wear, but that can go either way).
I can recommend Mike Busch on that topic (like somebody did earlier).
Leaning is not only for better mileage. The engines usually do not like a fat mixture for prolonged periods of time... I can’t recall all the reasons, but I think a couple of mayor ones were: 1) lead in the avgas will foul the spark plugs for rich mixture settings which is a safety risk, 2) exhaust gas temperatures will be lower which can lead to a build-up at the exhaust valves which can lead to wear and failure and 3) you end up with more dirt in your oil which makes engine corrosion even a bigger possibility...
Lean if you love your engine. And read Mike Busch - because he has the facts better than I do...
Some argue that the US won the WW2 War in the Pacific by running LoP with the P-38 Lightning.
Charles Lindbergh demonstrated to US pilots how to do it, based on his Atlantic crossing testing, and the result was double the range. This allowed the US to surprise and "outrange" Japanese island installations, and to shoot down Admiral Yamamoto at great range.
(I would argue that the full story hasn't been told of the latter, since the planning was literally perfect. Something like radio navigation would have been needed, or incredible luck.)
Outrange was a Japanese strategy to attack US ships without expecting a return attack because of the Japanese planes having greater range initially. ie. LoP disrupted Japan.
AOPA: Technique: Lean-of-peak engine operations
Keeping your cool on less fuel
There is of course a minority religious sect within GA who follow lean-of-peak theory and mess with their mixture constantly for better mileage (and possibly better wear, but that can go either way).