Nurturing relationships is an important part of my business model.  I need the ability to monitor touchpoints with my clients and proactively reach out periodically when there is a long lapse.  I was surprised to discover that I can't use this field to define any workflows or filters.  Would it be easy to add as a field that can be used as a condition?  That way I know if inactive days is "greater then X" it will trigger a reminder for me to follow up.  Or, I can just filter my contacts view to show contacts with no recent touchpoints/activities and manually follow up.