I've learned the hard way through other hobbies. There's always the suggested items "one needs" versus those go-to products you actually use. There's also the "right now" factor and "good enough" that you figure out over time. Books were my nemesis in the past. But I make copious use of the library these days. And I find that I make better use of the books I borrow than the ones I've purchased.
These days I opt for crafty gifts instead. The majority of my hobbies are funded this way.