How often do you fertilize grass?

Nice question. In some website, they suggest that it should be at least three times a year but on my own opinion is, it depends how your lawn react to your style of taking care it. If you can see that it starts to have a yellow color then apply my technique. Use the cheapest fertilizer that is applicable for all

vegetables, just spread it around the affected area and water it for at least 1 inch deep, after two days of not watering, spread some sugar around the affected area again then water it normally. After two weeks, you can see some magic results. God Bless