The Google My Business help section added a new page for working with third parties - it aims at giving business owners guidelines when selecting a local SEO company or consultant.
While Google My Business is free, third-parties often charge a fee to manage your listing. They can provide valuable services like keeping your listing up-to-date, providing you with customer insights, answering your questions, and responding to reviews. It’s important to understand the benefits you may be getting from a third-party so you can evaluate whether you’re getting the best return on your investment.
Here are the five "best practices" Google listed:
- Be selective
- Work with one at a time
- Educate yourself
- Trust experience
- Evaluate your performance
The document goes into these in more detail, but I wanted to screen shot it just in case Google changes it in the future:
Forum discussion at Local Search Forums.