I differentiate between the money I spend on material goods & money I invest in my education, though I don't do this on paper. I figure most of what I've spent on vaping supplies was actually educational expenses & I don't even try to keep up with those. It takes what it takes to learn what we learn, & so far for me it's been worth the cost because I consider knowledge to be priceless. (Your knowledge is your most useful possession, & you'll probably never wear it out.) 