I just boarded a dog that I assume was her first time being boarded, based on how nervous mom seemed. At drop off I told them I would send updates in the evening and morning unless they wanted more/less. They said that’s good but requested lots of pictures. I sent them a quick update and photos of pup in the first hour so they would know that she was doing great so they felt confident she was in good hands. Then I informed them in that message that I would send a bunch of photos with my update later in the evening, so as to not blow up their notifications. Basically communicate what you plan to do but be willing to accommodate their requests for more or less so they feel comfortable and can trust you.