Your water pressure regulator is mounted on your incoming main water line, just passed the main shutoff valve. In my area, all homes have regulators and they are usually outside the house.

If the street pressure exceeds 75-80 psi and you don't have a regulator or your regulator is defective, you'll see leaks.

There is no set time to repair/clean/replace them. You do it when you need to.

Google it and see what it looks like so you can determine if you have one or not.