There is no limit to how many Call Actions you can set up for your business. The more Call Actions you have set up, the more questions your agent will be able to answer for your customers. Be sure to routinely check the Insights page to understand what phrases your agent did not have an answer for and set up them up as a new Call Action.
In terms of the Call Action Request Phrases, the more Request Phrases you customize your agent to recognize, the better your agent will be at understanding callers’ questions and answering them correctly.
For optimal agent learning, try to program your agent to recognize 10 different Request Phrases. The more exposure your agent has to various types of questions your callers may ask, smarter your agent has the ability to be over time. Also, make sure that you don't repeat the Request Phrases across multiple Call Actions (for example, using "coffee" as a Request Phrase for separate Call Actions). Otherwise your agent might get confused and give the wrong answer to your customers!