For a "one of" type job, I don't mind spending a couple $ at the LBS.
I'm going to redo my brake cables "one of these days", since they need to be a bit longer with my different bars. I could buy cable cutters etc. for probably a one time use or pay to have it done.
I won't have any problem with having them do it. I try to "throw them a bone" once in awhile for the free advice they give.
I wouldn't let someone else change the oil in my car (when I had one) however!