Possibly 4 Years:

My music hall of fame is so big, that listening to every song in it 100 times (not just across my lifetime, but on this computer, ie, in just the recent past onwards) is a massive project.  In fact, it may take up to four years.  It may even outlive my computer, which would make the project unachievable. >.<

Well, if the computer dies before the itunes counter ticks to 100, I won't reset my count.  My next computer will be allowed to just carry on the quest from there and finish things up.  In truth, I've listened to most of the songs in my music hall of fame 100 times over the course of my lifetime, but part of the music hall of fame's intended purpose was to get me re-acquainted with music I'd been ignoring for years or decades, so it really doesn't count that I once valued this music long ago.  If I don't also prove I value it now, then the music isn't great anymore now is it?

It's okay to start ambitious long term projects.  The next Olympics is already slated to occur in four years too, people are already planning and building for it.  (Beijing 2022).  I've already spent years just getting to this point.  First I had to listen through all the Tales music ever made 100 times, then Final Fantasy 15's soundtrack 100 times, then I spent a year coming up with the idea of a music hall of fame and finding all the songs that might belong to it, culminating in the Motoi Madness music I found just a few weeks ago.

Now that the Hall of Fame is fully constructed, I can get down to the business of listening to it.  But there's no rush.  It took a decade to fully construct my top 200 anime hall of fame, and it will take many years more than that to fulfill my pledge to have watched every episode of great anime not just once but twice.  I'm on schedule to fulfill that promise, but it is a rather massive one, just as ambitious as listening to all my favorite music 100 times in recent terms.  I'll undergo any challenge for the things I love.

It was a huge challenge reading all the authors' best series/works in my good books hall of fame.  I'm currently reading Gate.  In April I'll read Death March, and then that goal will be fully honored.

It was a huge challenge reading all the top 10 visual novel franchises in full, but I completed that last year with Really? Really!

It was a huge challenge reading all the good manga in my hall of fame, but I'm up to date with that as well.

It was a huge challenge beating Mega Man 9 and 10, but in the end I beat them.

It was a huge challenge getting my 17 alts to level 101 in World of Warcraft, but I did it.

It was a huge challenge building and playing 68 unique 60 card Magic decks but I did it.

So what if it takes four years.  I plan on doing it all the same.  My only regret is it means I won't be able to listen to the music that's already crossed the 100 plays threshold for four years -- including my Ogre Battle march of the black queen music.  >.<.  That's some of my favorite music!  Well, maybe I can occasionally indulge in it like a guilty pleasure every now and then, even though it will slow down the pace of my overall project.

The current plan is to watch the Olympics (starting today, when figure skating begins) until the 22nd, when figure skating ends, and then start playing Dynasty Warriors 9 starting on the 23rd.  There's not enough time to do both so DW9 will just have to wait.

I should also finish the rewatch of Kyoukai no Rinne and the Gate light novels during this time.  Then March can be fully devoted to DW9, March Madness, Jessica Jones season 2, etc.