The shop told him to tell her that she needed a panel upgrade...
That's not upselling, that's fraud. Good on him he quit and went to a more reputable place.
The co I work for now allows us to pitch upgrades to the customer if we feel they are needed. This is includes fixing anything inoperable or broken, code violations, replacing old lights with LEDs, replacing devices with TR and/or grounded units, bringing things up to current code (like in-use covers on exterior receptacles), and additions like extra lighting, better products, etc. We do not hard sell these things unless we consider them a major safety issue.
Example: Saturday, customer wanted two old lights in kitchen removed and two new ones hung, along with some repair work. One light was very off center of where their new dining room table was, so we suggested moving the fixture over the table. They agreed. The repair work, we fixed the original install to work as they wanted it instead of a stop-gap measure they had suggested. They were happier and we made more money. Win-win.
The company is small, but we do get incentives. Some are:
1) Getting paid full day's work if we are efficient and get the job done faster
2) Get a % of any work we upsell.
3) We get a say in how the work is to be done. This may not sound like an incentive to some, but having the boss listen to and accept your input goes a long way to job satisfaction for me anyway
4) We get paid lunch breaks and paid-for lunches on weekends
I will say if you're a small outfit (1-3 employees under you), that going on vacation and leaving your employees w/o work that week or two is no good. They either need work scheduled that week, a partial/full paid week off, or loan them some money, SOMETHING. Leaving your people high and dry because you cant not micromanage, or trust them to work alone, or schedule sufficiently in advance is bad business. I hear guys griping about this all the time. Sitting on your butt not making a dime when there is work that could be done is incentive...to seek employment elsewhere.
One of the biggest free incentives you can offer is praise. If an employee does a really good job, or goes out of their way for you, or comes up with a cost-saving measure, THANK THEM, SINCERELY. People want to feel important, valued, recognized. It doesnt cost you anything to tell someone they did a great job.