Speakers to hang on to for LIFE

After 9 years with my Proac Response 3s, I recently decided to change speakers. As you can tell, I'm not an upgrade fever patient. I want something I can live with for years & I think the best advice I'm gonna get will be from those who have & are still living with their speakers for an extended period of time. Please tell me why too. Thanks.Bob.
Polk Lsi15. I have had the urge to 'upgrade' for 9 years. But there is nothing out there that would be an 'upgrade'. Sometimes we have to accept the fact that we did it right the first time. Which is what the OP's post implies.
When I was a kid I hung out at a place called The Stereo Studio here in the Chicago area. My first pair of brand new loudspeakers were purchased there one night at a "Midnight Madness" sale. I bought a pair of AVID 102a bookshelf speakers for $119.00 ea. plus tax. Today those little gems are in my garage where they serve me well while cooking out or just sitting outside with my wife and son. Not hardly the BEST sounding speakers I've ever heard but very decent little bookshelf speakers never the less. I was just a kid at the time and couldn't afford the high end listening room. But I zoned in on a pair of KEF 105/2 Reference Speakers that just sounded so great powered by a pair of big Audio Research Power Amps and eventually I took them home. They are still with me 33 years later, crossovers freshly rebuilt, woofers re-coned and they sound and still look terrific. A few years later I managed to score a pair of KEF 104/2 Reference speakers as well and I still have those too. There's just something about these loudspeakers... they are truly special to me. These will be with me until the very end.
I'll have to agree with the KEF 104.2. They should be "old and in the way" but I have mine powered with a VAC Avatar in triode mode, and there is something about the midrange that gives pleasure, and can sound spooky real. I have an itch for the Aerial Acoustic 7T, but it's like replacing a pet that is still living at the house.
I would nominate two - the bookshelf ProAc Response 1 SC and the floorstanding Tannoy D-700. After almost 20 years with both, I still find them thoroughly enjoyable.
I just upgraded the stat panels on my Innnersound Eros Mk II's to Roger Sanders new stat panels.

Broken in for past month and they are the most revealing, dynamic, resolving and uncolored speaker I have ever not heard.