Also depends on your type of grass. Kentucky blue does well letting it grow higher, but St Augustine does better kept short. Seed vs runner. Seed can always patch spots, while any dead spots on st augustine is a bitch to get to fill in without actually buying patches of sod.
I've lived in my place for about 4 years and I'm still working to repair the damage left to the yard by the previous tenants without actually buying all new sod. I've managed to rid it mostly of weeds, save for a few spots of crabgrass that love to grow in the dead spots. I also have mowers, so they're constantly depositing shit from other yards, but still a much better, cheaper and easier solution than doing it myself. Nature really fucks me up, was out for 2 weeks for a sinus infection the last time I mowed the lawn myself. Honestly wouldn't mind doing it myself, but I have a pretty big fuckin yard, and allergies suck my dick with heavy teeth. I still fertilize and treat for bugs, and have a weed extractor I use regularly.