It’s important to make sure your lawn is well maintained especially if you want to keep it healthy and extend its life.
Mowing regularly can help, and obviously this is not possible during the winter, but during the warmer periods, mowing as frequently as once per week can certainly help. Weeds will appear from time to time, and ripping them out from the root or suing weed killer can help make your lawn look good.
Watering a lawn during the spring and summer can also be beneficial, but not essential. An established lawn will not need watering as it will not die without water, however, watering is required if you want your lawn to maintain its greenness. Finally make sure you do not feed your lawn during winter, after March you can because frost-free conditions are likely to have drawn to a close.