Privates are open to people we know and never removed. This is people we have met or those certed by peeps we know. They are initially opened to profiles we approach and/or profiles who approach us open that we are interested in. Within those, some move to known status and others are removed as we or they lose apparent interest. I track these by putting "prospects" in favorites also. That list is smaller than private access list , easier to navigate and see notes etc. We also use favorites as are tracking and the list we discuss together when making our decisions. So as prospects become non prospects they are purged, notes updated and no longer on our radar. Without this you lose track and leave Privates open forever as its only two options on or off.
Personals aren't released much unless a prospect opens pics that match that folder ie naked and limited X pics. Typically I do that for a week or two as they make their decisions. The only one with long access is US LOL.