I disagree completely.
Sorry Jack, have no idea where you came up with you list. Seems like a list of things you personally do not want to do but that has nothing to do with their ease of completion nor profitability.
I do agree to stay away from payment plans unless you have a relationship with a finance company.
We successfully exchange laptop screens and after you do a half dozen or so they are all pretty much the same. It is a nice profit center for us. The same is true of smart phone support. 15 minutes work and $89 profit.
The fastest growing profit center in the last five years has been home theater and surround sound installation and support. If Bestbuy can do it, usually individual IT technicians can do it better.