I'm new to lawns. I don't even know what kind of grass I have yet but I need to purchase a lawn mower. I've been looking at reel and electric mowers but the highest setting I've found on a reel mower is 3" and 4" on an electric. Will this be high enough? All the posts I've read say use the highest setting on your mower but here I have a chance to choose what that high setting will be. Is there a big difference between 3 and 4"? Do I need a higher setting?

I don't need a perfect looking lawn. I do want the least maintenance possible in terms of weeding, watering, fertilizing, while avoiding chemicals.

Thanks for any advice.