Most sources I've seen say a minimum of 500 rounds with no stoppages is the criterion for establishing reliability if the gun will be used for carry/personal defense.
For a range toy? Whatever floats your boat.
But there's a big difference between "break-in" and establishing reliability. Some of the premium 1911 makers (yes, I'm talking about Les Baer) won't talk to you about malfunctions unless/until you have put at least 500 rounds through the gun. To me, that's unacceptable. If I buy a new car and it keeps stalling every half mile going down the road, I'm not going to wait for 500 miles to show on the odometer before I take it back the dealer to fix it. I buy a car to take me from point A to point B. I buy a gun to send a projectile in the general direction I'm aiming when I pull the trigger. Both are machines. If either machine doesn't perform the intended function, it's defective and should be repaired or replaced by the maker.