At one time my thrifting activities were randomly acquisitive.
Sometimes there's a strategy in that. Amy Dacyczyn once wrote about trying to scrounge cross-country skis for her family of eight. After passing up some partial sets, she realized that, having lots of storage space, she would do better to accumulate a big pile of boots, poles, and skis in different sizes, and then match them up to her people.
As young parents, we did the same thing with little-kid clothes: if a baby or toddler haul came along, we saved as much as we could for the next nothing-fits emergency. I accumulated craft and sewing supplies, and kids' books, although I was pickier about those.
Now, living in a smaller space and with less maybe-someday storage, I have to be more intentional about what comes home. Of course we are also beyond the stage of saving up kids' clothes and learning stuff. And at this point you might think my whole point is going to be "buy less, don't accumulate."
Well, sometimes you do buy less, and sometimes you don't. Like Amy, you may be over-accumulating with a purpose. Maybe you want as much red, white, and blue yarn or fabric as you can find, because you're planning a patriotic afghan or quilt. That's intentional. Maybe you need a hundred canning jars, because you're going to give everybody salsa and jam for Christmas. Or a bunch of flowerpots, because your plants are growing like crazy and need to be shared. Or every travel guide and history you can find about your bucket-list place, so you can plan a better trip. That's not hoarding, that's intentional.
My personal-stuff and home-stuff thrifting over the last couple of years has gotten more intentional, and that's developed a strange side effect. I now wander into thrift-store aisles that I used to ignore, and ignore the ones I used to spend all my time in. I price adult books, not children's, and I rarely look at the kids' books out in the store; I just don't need any. Until recently, I would never have bothered with business books, but I'm finding now that some of them are helpful in the courses I'm taking. Our needs change.
You can thrift more intentionally when you've narrowed down a basic colour scheme, or when you know what the gaps are. Our main living space here has a lot of beige, brown, and green, plus some floral things here and there. If I saw some table linens in those shades, I might pick them up; but not if they were neon pink or black striped. My eyes have gotten trained to think "yes, that's like our living room."
Very recently, I found a purplish button-up cardigan on the 75% off rack. It will go with all my favourite scarves, and my grey skirts and pants. Yes, it's May, but I'm putting it away for fall.
And that's intentional.