Anything in range of 49152-65535 is unreservable port numbers in IANA, so these numbers are generally safe. So using this safe range means it is less likely to collide with any running apps and thus, reduce the time to find a good port number.
http://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers#Dynamic.2C_private_or_ephemeral_ports