Maintaining a lawn takes a little bit of tender loving care every so often. The great thing about a healthy and well cared for lawn is that once it is established and doing well, it pretty much takes care of itself. A strong stand of grass will actually choke out weeds just because it is protective of the ground and sun space the grass uses to grow and thicken. For the most part, your lawn gets what it needs from the rain, an occasional watering and the soil. And if you give it a little fertilizer every once in a while, that helps things along as well. But you don't need to do that more than couple times a year because you can do as much damage over tending your lawn as neglecting it.
The one routine maintenance step you should plan to work on probably around once a week depending on growth is mowing the lawn. It sounds like this is just a basic step to keep the lawn from looking ragged and to keep the neighbors satisfied. But mowing does a lot for your yard to keep it healthy as well. Grass is unique among wild vegetation because it thrives on being mowed. The cutting stimulates growth and spreading. If some or all of the cuttings get down into the soil, that provides mulch for nutrients.
But maybe most valuable is that weeds do not thrive on mowing. When you cut off the heads of weeds, they do not have that upper growth to gather sunlight and produce spores for reproduction. The weakened weeds are then easy prey for aggressive grass sprouts to crowd them out of your yard. In that way, mowing is a natural form of weed control. This is why early in the season, mowing low works because not only does it encourage grass growth but it sucks up much of the residue, which prepares the turf for new growth. In addition, you want a relatively clean grounds early so the fertilizer you put down to jump start the yard can get down to the roots.
But as the summer progresses, lawn experts call for raising the blades of your mower so you are cutting the yard higher and leaving it somewhat longer than earlier. This encourages root growth. And the deeper the root system, the better your grass becomes at finding water and nutrients. The more well established your yard will be which helps it survive the dormant months ahead.
The court is out on whether to catch your grass or to allow the cuttings to go into the soil for mulch. In general, you will get some residue from mowing even if you catch and that is probably sufficient mulch. If you allow too much mulch, it can become a "thatch" which restricts airflow and even water penetration to the roots of your grass. So be smart in how you approach even this basic task of mowing your lawn so you are doing so in a way that encourages long term growth and health for this important part of your property.