This is about Phoenix installs but applies to ALL regulator service.
I realize folks like to be frugal......Saving money is not a bad thing but being penny wise and pound foolish is another and could be potentially dangerous!!!
Photos below are from two different regulators that had Phoenix first stage put on them......Neither regulator had any of the other original parts changed on them by the person who did the work and the owner was wondering why neither of the breathed very good and why one freeflowed out of control after using it a couple of times.
Do not re-use 50 yr old perishable parts.....Do Not use silicone gasket adhesive to seal between the body and can.....Bigger the glob better the job does not apply when installing DBE's.....
Bottom line........SERVICE IT RIGHT THE FIRST TIME.....IF YOU DON'T GET YOUR OLD PARTS BACK AFTER YOUR REGULATOR WAS SERVICED YOU GO RIPPED OFF AND YOU ARE DIVING WITH A REGULATOR THAT HAS A HIGH PROBABILITY OF FAILURE.....