ADM serves Car Dealers, Automotive Marketing Pros and Internet Sales Managers
I have to agree with your point Mitch, we're always getting cold calls from automotive magazines and various trade mags pitching ad spaces on their publications. It's very costly and we haven't had much luck from it.
The benefit of Adwords is that you can really cherry pick high quality search queries which are what the industry calls "buying" or "high converting" keywords.
I prefer the consultancy route as opposed to the inhouse route though, I've attempted Adwords a couple of times and did not have much success. We'd always spend a lot of money and all sorts of traffic with little results. Because we're an industrial/automotive computer supplier we tend to get a lot of consumers clicking on our ads looking for end user tablet PCs. After hiring a consultant he was able to get our ads only displaying to the automotive market with precise keyword selection, his website is here. Certainly if you have time to learn Adwords you're better off doing this in house. However outsourcing was best for us.
Here is the bottom line! If they are willing to bring someone in-house to manage the PPC as their first priority, then I say that is the time. If PPC is going to be a persons second or third priority, then they are setting themselves up for problems. Simple as that!
Yes, bring in an expert to do it, no ifs, no buts. Getting an amateur to do the job is asking for trouble. Especially when they're managing fairly large budgets, even a relatively small adwords budget like 3K a month - it's best to have a professional manager do it.
Though you'd need to have a very large campaign if you were to hire in someone to do it inhouse. SMEs generally only require 20-30 hours a month in management. Not enough to warrant hiring someone full time.
My experience has been that it's pretty difficult to find and recruit a sole PPC manager to do this kind of job. There are few people skilled in this area, staff turnover for these web related jobs are pretty high too. Even for a large firm we always had staffing issues where web marketing personal with jump from one firm to another. Skills are in high demand, supply is limited. Staff always get poached.