That’s a great question. I’ve always thought of lead progression more like the purple line in this drawing as opposed to the red. In general people are always moving forward, but they often stall - and that can happen at any stage. Because of this, I use ‘time-in-stage’ values to trigger actions that might help move that lead forward again. Lead stages are used to communicate how far that contact has progressed (so they don’t change). With one change to what you have 
, which is that Unresponsive is a Disqualification reason as opposed to a stage, and I use a workflow to set that Disqual reason after the person goes dark for X # of days.
Some examples:
* Time in Diqualified is 3 months and disqualified reason is none of email bounced, not a fit etc.
* Time in Opportunity is 1 year and Opportunity is Closed Lost.
* Time in Attempted is 3 weeks and last activity from contact is 2+ weeks ago.
Good luck!
