When I'm not diving with a charter, or with a charter that does not provide the service, I put my own rig together and disassemble it. When I'm in a tropical location with a full service dive op that provides the service, I'm more than happy to let them do it for me but of course I'll check it over carefully before diving it. Those divers who say "I never let anyone touch my gear because I do it better than the guy who does this 100x per day" can die on their own hill or however the expression goes. Putting a rig together especially when you do it over and over again because it's your job, is not rocket science.