Yep. If we argue for time of value money hoarding your cash in an investment account, why cant we calculate quality of life money too
Well, of course you should.
There are two parts to any purchase. First,
what does it cost? That's just math, and as Mr. Incredible reminds us, math is math. TVOM is a mechanism that allows us to compare costs that are spread out in time to an equivalent cost in today's dollars as a single purchase. If we are considering alternatives, we can use this mechanism to compare the costs of those alternatives.
But, that's only one part. The other part is
how do I value it? This is not just math, and unlike math it is going to be differnet for different people, becuase different people value different things. For example, I don't drink, and Disney's mocktail menus haven't caught up to the outside world. Because of that, I assign a lower
value to the Dining Plan than someone who usually has a cocktail with dinner. And even that is probably too simple an example. A better one might be: I don't particularly care about being able to walk to a theme park, and I really hate the idea of packing and unpacking. So for me, a split stay sounds like torture, whereas for someone else it might be an ideal way to structure a vacation to walk almost everywhere.
I can also tell you that ignoring TVOM makes you a timeshare sales agent's best friend, becuase you are under-valuing the "cost" of the up-front purchase, and that's the part that generates commission and puts bread on that agent's table.
I have a great story of my brother doing a Hilton tour way back in the day. He has an MBA from Michgan; his wife has one from Notre Dame, but we love her anyway. The agent tried to use straight division to spread the initial payment over a longish ownership horizon, and my brother---a person who
definitely understands TVOM---called him on it. The agent did it again about fifteen minutes later. It was at that point that my brother looked at the agent and said: "Look, we already talked about this, yet you keep doing it. So, you either assume I'm an idiot, or you actually are one. Either way, our conversation is done."
Boom: Sent directly to gifting to get him off the sales floor.
Now, it is true that you have to make some assumptions about the rate. But that assumption is not too difficult; it just depends on what, specifically, you are comparing. The details are left as an exercise to the reader.