Ideally before you go on a genealogy research trip, you’ve made a list of the records you want to search, where they are located, etc. The reality is that many people don’t do that.
One thing you don’t want to neglect to do: check the hours of the facilities you will visit, determine their access policies, see what cameras and scanners are allowed, etc.
It can be a waste of time if the facility is not open when you “guessed” it would be, if records are off-site for one reason or another, or if you can only take a pencil and paper into the records area. These are things you need to know before you ever think about heading to perform on-site research a distance from your home.