How many mortgages can you have?

[Asher Anthes]

I've heard 4 and 10?

What I'm thinking about doing is buying a house once a year moving every time, so essentially I would have 4 OO financed rental properties. Each time cash out refi-ing up to 80 or 90% and using the money for cash flips or cash buy and holds. Is the mortgage limit 4, or could I theoretically just keep doing this over and over.