After dozens of charter trips, I have learned that you can't spend too much time with the checkout skipper. Be sure to go over all the systems on the boat, particularly electronics and plumbing. Where are the through hulls, how to switch fresh water tanks, how to check all tank levels, location of all breakers and other electronic switches, and so on. It is a good idea to check to make sure that all of the heads are flushing free and you know how to switch back and forth for the holding tanks. And so on. No matter how much time you have spent on other boats, you will discover idiosyncrasies on your new vessel. Location of tools, flash lights, operation of the radio, autopilot controls, and so on. In my extensive experience, the more questions you ask, the more confident the check out person will be that you know what you are doing. Over confidence will not serve you well.