Should I Update SL?

I normally agree with your "not broken-don't fix it" approach but a recent example made me upgrade from SL to ML - which by the way - went perfectly !  The changes in the software are generally welcome and easy to figure out and  there were no problems. Pogue's Missing Manual is worth the moderate investment.  Now - the example...I generally go to every other new version in software upgrades, i,e. CS2 to CS4.  I was getting ready to upgrade from CS4 to CS6 and missed any notice - if any were published - only to find out that Adobe NOW requires annual upgrade and CS5 is no longer available !!!   I would have to buy the new version of CS6 @ $600 !!!  So I guess that I will stick with CS4 forever !