Here's my thought on the matter...

I've bought a few fairly "irreplaceable" guns because I wanted to use them with a plan to use them, add wear and tear, and generally consume them to the extent one might expect through ordinary use. Resale was just not a consideration. I pay for the gun and get to use the gun. There might be nothing left when I am done.

On the other hand, I've got some fairly ordinary revolvers that have grown on me over time and have become irreplaceable (to me) by virtue of proving themselves or riding with me on various adventures or for extended times. One example is my 12-13 year old Smith 442. It has a couple thousand rounds down range, a good bit of wear, but has gone to a lot of places with me. In part, because I viewed it as expendable. It's one of those guns that I would back in my checked luggage, etc. It is easily "replaceable" by most standards. These days, I would not sell it for $2000.00, or more.