Unlike other types of refurb items, speakers, especially TV speakers, basically just sit and play sound. Damage could come as a result of blasting the sound too loud (which people rarely do), or as a result of physically damaging the speakers, but for the most part they just sit there and do their job.
Contrast this to something like a laptop, tablet, phone, mouse, etc. These items get handled frequently, they get moved around, dropped, bumped, kicked, sat on, and generally they just take much more physical abuse. You can turn up a laptop's speakers too loud, smudge/crack the screen, let it overheat in a backpack.. there's a lot you can do to screw it up. And if the hard drive is starting to go? That's not always noticeable.
With speakers, just hook them up, turn the volume up a bit, and make sure you don't hear any buzzing/hissing, and that the sound doesn't cut out randomly. If they do, send it back, but generally speaking (heh, speaking, get it? like, a speaker. speaking. get it? *nudge nudge*), a speaker is a pretty safe bet for a refurb.
I bit the bullet and bought them, hopefully theyre as great as they sound
(oh, i get it!)