Some other things to consider:
A format & reinstall is sometimes required but people do not always have the correct software & licenses. I refuse to load on illegitimate copy of Windows or Office (some people seem to think Windows includes Office) :/
Sometimes one needs internet access on the spot. I needed to help an elderly lady to install her HP printer on a new laptop the other day. The download was going to take FOREVER on her Cell C 3G stick. Luckely I could download the driver on my phone much quicker and could copy it to her pc that way...
Sometimes one needs to phone a SP's call center for assistance - not sure how many operate after hours. E.g. the person has forgotten their adsl or email password...
Sometimes new hardware is required e.g. router got struck by lighting, RAM is faulty etc.
Thanks for the feedback. Will give these challenges some thought.