How often to rotate depends on the car and your driving style. Some cars rarely need them rotated at all while some need them rotated frequently and most in between. Personally, I only rotate mine twice a year; I tend to drive light cars (my current car weighs under 2400 pounds; lighter with me in it than most cars are empty) with wide tires so I don’t put as much wear on them as a skinny-tired lard-bucket.
For brands, I prefer Toyo; a little hard to find sometimes, but reasonably priced and a great tire.
As for how often, I don’t go by age or miles; I go by their condition. If they fail the penny test or have excessive wear then UI don’t care how new they are, they get replaced. Conversely, if they have decent tread all the way across and show not even a hint of cracking or anything like that, I will use them no matter how old they are.
@Cruiser Actually, it’s not the thickness of a penny; stick the penny in edge-first and see if it touches Lincoln.
@john65pennington Yes, you can, and I would have a few times had I listened to the salesperson instead of questioning their competence and buying elsewhere. Now, the tire store nearest me is quite knowledgeable and competent, but not all are. Trying to tell me that the 175/80-R13 on my tires meant that I had 175mm sidewalls and that a 175/85 would be wider is a sure way to lose my business.