This tip is more aimed at drivers of cars with manual transmissions. If you have an automatic transmission, shifting will take care of itself -- but it's still important to have your car in the right gear.
These tips can also apply to newer transmissions that allow a driver to select gears electronically, like with a "tiptronic" or dual-clutch transmissions.
It's important to be in the correct gear when you're driving. If you have manual transmission, you will likely have noticed that driving in too high a gear for your speed and RPM range causes the car to shake and move slowly, commonly known as "lugging." Lugging creates an unnecessary strain on the engine and can damage your cylinder heads, leading to expensive repairs later on.
In addition, it's a good idea to avoid excessive engine braking. Engine braking is when you're driving in a higher gear, then downshift to a lower gear and take your foot off the gas pedal. This causes the RPMs to increase and the car to slow down without using the brakes.
While it's effective in slowing down the car, and can make going around corners easier, engine braking can produce excessive wear on your engine. It's probably better to use the brakes when you need to slow down, and then shift to a lower gear when you're at the appropriate speed. This also puts less stress on your clutch and transmission parts, too.
Our final tip is up next: Why it's not a good idea to drive with heavy loads.