Have you ever tried a pair of speakers and said this Is the last thing I will ever need.

Agree!!  Stay curious.  Whether it's your religious or political beliefs, technology, new music...whatever, remain open to new ideas and trying new things.  I too have been in this hobby for decades and remain fascinated with new products, new technology and the possibility of better sound in my listening room.  Having said that I can understand the frustration of the "merry-go-round".  There is a fine line between the joy of trying new equipment and the frustration of never feeling completely satisfied with your system.  Part of the fun of this hobby is the hunt.  Most changes I have made in my system were not the result of any perceived limitations of my system but were simply motivated by curiosity.  

I am not necessarily ready to "settle down" with my system but when I do the math  based upon my age and disposable income, I am running out of time and opportunities to turn over equipment.  For that reason, I am more focused on making right decisions.  I hope my recent purchase of a pair of Vandersteen Quatro speakers will offer me a degree of lasting musical enjoyment...but certainly there is not guarantee.   I do want to upgrade parts of the rest of my system to enhance and compliment the new speakers.  In the past when time was not an issue I do feel I was on a "merry-go-round", replacing parts of my system willy nilly with no particular end in sight.  Time is the enemy of us all...

"Have you ever tried a pair of speakers and said this Is the last thing I will ever need."

Sure, lots of times.

My most recent forever speaker was just delivered and setup in my house a couple of days ago. The Vandersteen Quatro CT. I will have more to say later. Listening to music right now.