[giardini]

That's called apartments. Most dwellers don't own theirs. Its a completely different living arrangement.

As soon as you have a common area or a shared wall, roof or other construction artifact you need an HOA of some sort.

[JeffSnazz]

Many single-unit family home neighborhoods do not have an HOA—people just get along or take their concerns to the town itself. I mostly associate HOAs with suburbia.