When does sabbatical start (and what is it, really)?

I'm bemused by how my thinking about sabbatical has evolved over the last several months.  (I am on sabbatical for the entire upcoming academic year):

• Having front-loaded my entire teaching load to the fall semester last academic year, I gave my last pre-sabbatical lecture in December.  I was conscious of it being my last lecture for over 18 months. Under the "sabbatical-as-concentrated-research-time" view, part me believe sabbatical started as soon as my final grades went in.  That wasn't a great interpretation, as my spring semester was so deadline-driven (proposals, papers, committee/university service, etc) that I got little new research done compared to my teaching-intensive semesters, and I was frustrated.
• The day of my last committee meeting on campus, I went home giddy, convinced that sabbatical had finally started.  This took the "sabbatical as freedom from meetings" view, as well as the "sabbatical-as-freedom-from-commuting-to-campus" view (I live an hour's drive from campus).  These views discounted the wave of "I'm really tired and need some rest before I can usefully think again" that characterized the start of summer.
• July 1st was my official first day of sabbatical, after which I could reasonably tell anyone who asked me to do any university work that I was unavailable (not that anyone did, but I still sensed power in the date).  This was the "sabbatical-as-owning-my-own-time" view.
• Solid progress on new research projects in new areas in the second half of this summer have been personally rewarding.  This is the "sabbatical-as-time-to-do-new-big-stuff" view.
• This weekend, I am conscious that the incoming freshmen are moving in today, classes start on Thursday, and I'm not responsible for a dang thing.  I'm gloating internally at all the university and department emails that I'm not bothering to open.  I've reconnected with the idea that August can actually be a relaxing and enjoyable part of summer; I could get used to that.  This is a "sabbatical-as-freedom-from-death-by-a-thousand-time-cuts" view.

Reflecting from my calm August deck chair, I see how much of my early view of sabbatical has been framed around the idea of "freedom".  That's somewhat sad, as it encouraged me to focus on the aggrevating parts of faculty life (which I do actually enjoy on the whole).  It also had me thinking about the end of sabbatical--the time when I would lose that freedom--from the time it started. Focusing on the looming end of freedom made me a outright basket case for the first several weeks, when I felt a responsibility to make the most of every single minute of freedom I had, like grabbing a precious breadth when coming above water.

Those early weeks of sabbatical actually weren't much fun emotionally.

With a summer of rest and reading behind me, my perspective is healthier.  Sabbatical now feels like the "responsibility-to-push-myself-in-new-intellectual-directions".  Yeah, that's what the official memos on how to apply for sabbatical said, but I didn't feel it in my bones before now.  Finally, in the week when classes are about to resume, I finally feel sufficiently rested and initially rejuvenated mentally to start the real work of sabbatical.  I'm just thankful to have gotten to this point with a full year still to go, and with enough productive work done over the summer that I know what to do in the times that I won't be lecturing, orienting, or otherwise sitting in meetings this week.  There's no more academic baggage to lose, so the true freedom of sabbatical can begin (apologies to Janis Joplin).