Provided it stays in top condition and does not, in its life with us, require rebuilding so costly as not to be worth it (which would be a very, very long time from now in any event), I think our Yamaha S4 is our piano for life. It was Yamaha's premier piano in its size when built. The action is amazing, and the tone is complex in a very good way. Like many lesser Yamahas, especially older ones, it is hardly unyieldingly bright.
It is actually pretty crazy how we acquired this piano. We bought it, very lightly used at what I thought was a great price, from PianoWorks in Atlanta (h/t to Sam Bennett). I found it online, learned as much as I could about it, and felt in my gut it was the right piano. I never saw or played it in person before buying it. I sometimes cannot believe that I did that. But I don't regret it -- it was "the one".
I do at times fantasize about having a second piano. I've become sort of infatuated with Steingraeber since thread a month or so here with the mystery reveal. And my grandparents owned a stunning mid-century M&H model A. They are now deceased, but sold it before moving into a retirement home. I know who bought it and, while I'm sure the piano now needs substantial rebuilding, I have fantasies of buying it back.