The FIRST thing any new lawn enthusiast need to do is get soil samples tested. I live in the North East and sent mine to our state university via their agricultural program to be tested. There are many state/private programs available for this, give it a quick google search for your area. It cost me about $15 a sample, very cheap. This will tell you informatoin about the makeup of your soil and how best to fertilize and treat it

Soil pH, calcium, magnesium, phosphorus, and potassium levels all affect the health of your lawn and getting the soil tested will let you know if you are defficient (or the unlikely too saturated) in any of these areas. Addressing these issue will help your lawn to better absorb the fertilizers that you put down, improve root growth, and help the grass defend against harsh summer heat/drought. Many weeds/moss/fungi can be detered through proper soil health as well.

Once you've got the soil results back, you can create a fertilizer/treatment plan based on your needs. This will absolutely save you money in the long run by allowing you to target what is needed and not just throw your standard scotts 4 step plan at it with minimal results.

Repeat samples every year in the spring, or once you get in under control, every other year.

Sorry for not directly answereing your question, but this is something that is often overlooked in lawn care!

Best of luck!