So this is my humble 3-watch collection: SPB143, Prx 35 and Smiths Everest (and actually skx009 as well). I feel these fit all the needs I have at the moment and I really like the watches.
However, when I tried on the Tudor BB54 in april I signed up on the waitlist to buy it because I thought "This is it" and it is now waiting at the AD for me. For money reasons, I can't really justify to keep my current collection as well. And a BB54 would probably neglect the need for the Spb and everest as they more or less fill the same function. For a long term GADA, I see myself owning either a Explorer 1 or a BB54, being a fan of the smaller format.
Now that I have the opportunity to buy the BB54 I am a bit torn on what to do as I quite enjoy my current collection...
I therefore seek your advice: Would you keep this collection or would you sell it off and add a chunk of money to get the BB54?
I've done this exact thing...sell off a versatile collection of watches to fund a more singular "grail" purchase. In fact, I've done it twice (once being for the BB58). In both cases, I found that a one (or even two) watch collection falls short of feeling well rounded, and I quickly get annoyed/bored. In both cases I reversed course, sold the grail, and diversified my collection again.
Like you, I have a number of expensive hobbies, and I just can't justify tying up more than several thousand in watches. So, I've end up determining that, for me, a modest, rounded collection of watches in the 500-1500 range is where I'm comfortable. YMMV, of course, just sharing my personal experience.