Some people will know these things due to previous experience. Some through training. Some through common sense. But you cannot assume that your employees know what you consider to be the important element of politeness with clients.
Here's a video where I talk about What Would Your Mother Do?
Many new employees simply don't have the experience of of older employees. Not knowing the little things that matter in customer service is NOT a function of age. It's a function of experience and training. If you want your technicians to spend thirty seconds chatting with the person at the front desk, you need to tell them that. If you want them to park at the far end of the client's parking lot, you need to tell them that.
This is part of your culture and your branding. As part of your culture, existing technicians will train new technicians in all these little things. As part of your branding, your clients will see that your employees are well mannered - and that helps their perception of you.
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