The answer for me seems to be my prohibition against looking for free and bargain books. Can't be tempted by what I don't see. I've picked up some free books, and that's fine as long as I don't go looking for them. Also, buying only what I intend to read right away makes me think a bit before hitting the 'buy' button. I've bought only four books so far this year and have read all four.
I've always loved browsing at libraries and book stores, including on-line. Now I'm browsing my Calibre library. Keeps me focused on what I have instead of what I don't have.
BTW, tent camping road trips are tough on ereaders. I'm trying to toughen myself up for a long-distance back pack trip when my new knee feels less wimpy, so have been camping in and around Death Valley all this month. My ereaders have sand lodged at the bezels, and I have new appreciation for my bezel-less, mostly sand-free Kobo Aura. My Paperwhite has a new scratch on the screen so that I'm keeping the light off entirely. The good news is that when I'm ready to rejoin civilization, if ever, I have an excuse to buy a Voyage. In fact, that was the first thing I thought when the metal hit the Paperwhite screen. Tragedy turned to opportunity in a heart beat.