Out in the field, the Onsight app does not ordinarily use much mobile data because it works completely offline. Browsing the products in the catalogue and creating an order uses no mobile data at all since all that data is stored locally on the device. The only mobile data that is needed is when a completed order needs to be sent to the office. Of course, any new product info and images that are uploaded by an administrator will need to be downloaded by all the users so that they can have the latest catalogue. If you are in the field when these new products and images are added then this will use up your mobile data. If you wish to conserve mobile data it is best to sync your catalogue when you are at the office and connected to the WiFi network.