Summarize:

Gas-powered push mowers tend to be the most common choice for the typical suburban home lawn, but you actually have several options:  Manual reel mowers are powered only by you pushing them, and are an affordable and environmentally-friendly choice for very small, flat lawns. Electric push mowers are quieter and cost less to operate than gas models, but they're also heavier and more expensive. Corded models in particular are best suited to small lawns (0.25 acres or less). Gas walk-behind mowers come in both push-propelled and self-propelled varieties. Either is suitable for lawns up to about 0.5 acres in size.  Riding mowers cost more than walk-behind models, but will save you time with most lawns over 0.5 acres in size. They aren't safe for use on steep hillsides, though. Dull mower blades cause jagged cuts in your grass blades, which create brown tips and invite grass diseases. If your lawn looks ragged after a mow, it’s probably time for a blade sharpening.  You can expect to need to sharpen them 1-2 times per year. You can remove and sharpen the blades yourself with a few tools and some mechanical know-how, or you can search for "lawn mower sharpening near me" to find local pros. Even if your blades don’t seem to need sharpening, inspect them for damage every 3-4 mows, and brush or rinse away any built-up grass debris on the blades and underside of the mower. Many people mow their lawns too short in an effort to reduce how often they need to mow. This, however, leads to brown lawns and more weeds. Ideal mowing heights vary based on several factors, but usually fall within the range of 2 to 3 inches (5.1 to 7.6 cm).  Measure from the ground to the bottom of your mower’s mowing deck, then from this point up to your blades. This total equals the mowing height. Look for mowing guides specific to your lawn type, such as https://www.lowes.com/projects/lawn-and-garden/mow-your-lawn-correctly/project. You can also contact your local agricultural extension program for advice. It is unsafe to add fuel to a warm mower engine, so give the fuel tank a fill-up before you start mowing. Check the oil level every 2-3 mows as well, and add oil as needed before firing up the engine. You’ll also need to occasionally change the oil and clear the fuel lines, or have a pro do this routine maintenance for you. Consider giving your mower a tune-up once a year at the beginning of spring. Some people mow their lawn like clockwork every Saturday afternoon, but it’s better to mow based on the height of the grass. Use the “1/3s rule” and don’t mow down more than a third of the total height of your grass each mowing.  So, if you keep your lawn at 2 inches (5.1 cm) high, wait until the grass is 3 inches (7.6 cm) high before mowing it. Check the weather forecast for dry weather as well. Wet grass can clog your mower, make compaction in your yard, and make it too slippery to mow safely. It’s better to mow in the evening after a dry day. This reduces clumping, lawn damage, and heat stress on the grass (and you). So plan accordingly. Walk around your lawn and pick up any branches, rocks, toys, pet waste, or other obstructions that could damage your mower or make a mess. Even more importantly, send your pets and kids inside, or at least to a secure area away from where you’ll be mowing. Some mowers can eject rocks or other flying debris at dangerous speeds, so it’s always best to keep other people and pets out of the area. Wear safety glasses to protect yourself from flying debris, and ear protection to muffle the loud mower engine. Also put on closed-toe, sturdy footwear and long pants to protect your feet and legs.  Put on sunscreen and wear a hat, even on cloudy days or if it's early or late in the day. Be sure to stay hydrated. Take breaks if you're mowing a large lawn, feel overheated, or start to feel tired.
Use the right mower for your lawn. Keep your mower blades sharp and clear of debris. Set your mowing height based on your grass type(s) and climate. Check the fuel and oil levels before starting the mower. Mow your lawn on its schedule, not yours. Clear away lawn debris, pets, and kids before mowing. Put on protective eyewear, ear wear, and clothing.