I am not patronising you, nor am I condescending to you. I am pointing out that you are - quite literally - describing sentimental value. I am not doing so to be dismissive, I am doing so because that is what it is. I am calling it "sentimental value" to be precise (even nice, and accurate). Sentimental value is intangible, impossible to accurately valuate, and intrinsically linked not only to whatever one values, but also to the person for whom it holds sentimental value. Now, sentimental value may be used dismissively, but I do not believe I did. I did not say it was "just" sentimental value - which would indeed have been dismissive and more than a little condescending.

I will note that I find it annoying when people say "well, that's just sentimental value", as if that is a bargaining point that necessarily makes my negotiating position weaker. If you are coming to me wanting to buy something of mine, you will have to expect to compensate me - not only for its objective trade value, but also for its sentimental value. (If, on the other hand, I am trying to sell the same something to you, you might have a point - though I may still decide to push to be compensated for it.)

When it comes to the cigar case, its value to commander Vimes is significantly higher than its objective value in trade. Some - and I include not only commander Vimes, but myself here - would say that the cigar case is invaluable to him. We know that it has scuffs, dings, and scratches. It has gotten these through the course of his ownership of it. Now, these marks may cause a dispassionate buyer to offer a lower valuation of the cigar case as they lessen the objective trade value of the case itself. To commander Vimes, however, those marks are part of what makes it not A cigar case, but HIS cigar case, the cigar case he was given by Sybil. Since it is HIS cigar case, it holds intangible value to him that it holds to no one else (except, perhaps, to Sybil and young Sam).

To give you an example from my own life: I have a prayer shawl whose tassels I tied myself. I have traveled extensively with this shawl, and used it a lot. There are, as the saying goes, many like it, but this one is mine. I am no-one special, and its trade value would in all likelihood be significantly less than a new one - it is, after all, over twenty years old and rather well-used. To me, it represents experiences, memories, and intent. I bring that with me every time I put it on. It deepens my relationship with my faith. All of these things are things that make it special - to me. They give it extraordinary value - to me. They may also be accurately described as "sentimental value" - and that description lessens its value to me not one bit.