&gt; When I hired a plumber for my heating firm, I put her through a hazing interview, tested her knowledge of Maxwell relations and thermodynamic equations. Oh wait, no I didn&#x27;t. As she has been a plumber for years, so we recognised her skill and experience and cut to the chase.<p>When I hired a plumber, I hired someone that was insured, had multiple good reviews online, and was able to give good, descriptive, and in depth details of the job he was going to do. Generally, a programmer will not insure their work, and usually you aren&#x27;t hiring for a single job that can be designed and discussed in detail up front.<p>Even so, some of the contractors were still pretty damn shoddy, and I&#x27;ve had to fix their work (or hire someone else to) in the past.<p>Part of the problem is that I don&#x27;t know enough about construction codes and the reasoning behind them to ask, eg, what kind of slopes and diameters pipes need to effectively carry sewage, when it&#x27;s appropriate to use one type over another, etc. If I could, I would.