7.5 I finally got around to starting up Telnet on my system. Am I incurring any performance penalty by having the default SERVICES, PROTOCOL, and INETDCNF files?

There is no penalty to keeping the default SERVICES and PROTOCOL files. But since INETDCNF controls what network services INETD is going to make available, it is always a good idea to comment out anything you are not going to use.