Time taken on the actual task and time the device is doing it's own thing do not factor in a labour charge cost. I have often charged a customer £20 for a job that took me all of 10 minutes. When they protest the fee I inform them I am happy to put things back how I found them and refund it, normally that is when you keep your earnings.
The types of people who bemoan the labour charge parts of any trade invoice are normally folks who have zero experience of any form of trade job themselves. What they fail to see is I do not charge £20 for that half hour of work I did, I charge £10 for the time and £10 for the knowledge in my head of how to do the job. That is the key all trades revolve around, anyone can fumble about for hours and charge the earth but someone with skill and knowledge has a valuable commodity as such they should not feel guilty for charging for the service they provide.
Also be very careful of feeling you should not charge as much because it's a friend of a hamster brothers second cousin. If you are going to charge for a service and you believe the service you provide is equal or better than a similar service you should be charging similar fees to anyone and everyone, otherwise go in to charity work and save yourself lots of headaches. It is one thing to have a quick look at grannys pc and get her wifi running but before long you end up having to talk about all this stuff round dinner tables and folks are picking your valuable mind for free tech support, try that with an out of hours doctor or accountant and see how they respond.
