What are lifecycle conditions?

Life cycle conditions can be set up for deals, contacts, organizations, and leads – their progress is depicted by movement from one stage to another in their life cycle. For instance, sales stages in a deal’s pipeline depict its life cycle from initiation to closure.
Consider the example below.
You can set up an alert on the Contact Status field in Contacts for when a contact has not exited the Contact Status – Inactive – since 10 days.