You are not thinking about the large picture.

Renting a tiller and throwing down some clover seeds is cheap compared to a lifetime of lawn people.

Just like with your first comment. Yes things break and are expensive, but you're not throwing ~1500 a month out the window renting.

Nah, the process you'd want to do is called over seeding. You trim the grass super super short, spread seeds, and that's it. You can get seeds and a spreader for pretty cheap. It's not as expensive as something like sod or ripping up your old grass.