I learned that the hard way. I use to opt for fast fashion shops (h&m, forever21, zara, etc) thinking I'm saving. But it wasn't until the pandemic that when I started selling some unused items to fund for what I want, it barely sold for half or wven 25% of what I spent originally on it. But other things I spent a bit more on such as Anine Bing t shirts, i was able to make back all if not 70% of what I spent on it.This is so true. I stopped buying cheap(er), casual bags for this reason. Some people do carry around their inexpensive Target or fast fashion bags for a long time and that's awesome - I just could never do it... something about the expensiveness and classic-ness of (some) luxury bags keep them in my rotation for a long time. For example I was out of my mind when I bought my Neverfull in my early 20s but 10 years on it's still my One tote bag for travel and work. It's well earned its keep.
Now when i purchase an item accessories wise, I hate it but to be realistic, I want to make sure I at least make back 70% of what I originally bought it for. At least that way, if I want to sell it to fund for a new item, I won't feel like I'm literally giving the darn thing away at such a low price.