Sets that I really, truly, intend to open and build I put in a completely different place than the sets I use for investment. It helps to keep them separate.
I don't consider them as sets I've bought from myself. But, I do put them into my Brickfolio (as a used set), and I do list them on my own tracking spreadsheet. My investment goal, right now (because I have kids that play with Lego) is to make sure that I first cover my "play" costs with my investments. So, my first goal is break-even. (There are other goals, but for the purposes of this conversation, that's all that matters).
But, sometimes I look at it individually. For example, last week, I flipped a few Star Wars Advent Calendars. I made enough from those to pay for the one calendar I wanted to make sure I had for myself.
I do consider some of the sets I buy, and open up, as potential future investments, though. I like the architecture sets, and enjoy displaying them on my desk at work. Usually, I will buy one set, build and display it, and then, after a couple of months, it gets torn down and put into the investment area. Yes, it's used. But, I look at the used vs new selling price, and make piece with the idea that any money I may lose having opened the set is usually such a small amount that I "paid" for entertainment. (e.***., if I lose $5 on a architecture set, I certainly got $5 worth of enjoyment out of it).