Your professional knows all this, as they use these products every day. They understand what type of grass you have and know exactly when it's best to fertilize in your region. They’re already doing this for a number of lawns like yours. They also bring the tools to safely spread the fertilizer over the lawn. When it comes to fertilizing your own lawn, most people tend to make mistakes. It’s a learning process. If you want your lawn to look its best, you should ask several professionals what they’d recommend in terms of a schedule and how much they charge. Their advice should all be similar. The only major advantage to doing this yourself is to save on costs, but most people tend to trust professionals for fertilization.