[jobigoud]

I used to do this a long time ago but now I find that picking books like this, semi-randomly, isn't a good use of time. Reading a book takes time and there is already more interesting content than I can consume. This means if I choose carefully I can spend all my reading time reading the most interesting/useful books possible, instead of being constrained to whatever the thrift store happens to have at this moment.

[retsibsi]

I think this is mostly true for me, but I wonder if the best approach involves a little bit of the 'semi-random' too. The internet is an amazing way to discover books and authors, and I feel like I'm exposed to a pretty eclectic mix, but I assume my discovery process is biased in some unhelpful ways. The payoff of discovering an entirely new (to me) and excellent author can be pretty great, perhaps even more so if their work is completely different from most of the stuff I read -- so maybe a bit of unguided exploration in unfamiliar territory is worthwhile, even if it's mostly unproductive? (Either way, I bet someone has analogised this process to some well-studied class of CS problem, and drawn interesting but practically dubious conclusions!)

[WalterBright]

I've discovered the thrift store books are not bad books, they tend to be popular ones that people already read and are just clearing out their homes. I've discovered a lot of very good books I never would have run across otherwise.

I look mostly in the scifi and history stacks.

As for my time, I enjoy picking through the stacks.

[dredmorbius]

Have an idea of the books you want to buy, and know roughly what the selection of such places is -- champaigne tastes in a brewpub won't fly, but if there are popular books or topics you may find, take advantage of the opportunity.

And examine books for mildew before buying. Though freezer + baking soda treatment does work.

[acdha]

Internet arbitrage caused quality to tank about a decade ago: any time there’s a sale, note the people cruising through checking prices on their phones so they can pick the books with significant resale value (the used bookstore owner probably does this too, if they’re still in business).

[WalterBright]

The thrift stores do that, too. However, I've found that a book's resale price has little correspondence with its quality - more like how many of them were printed.