I make it a practice to purposely seek out refurbished tech items because I save a ton of money doing so, and the majority of the time the whatever-it-is I buy works just as well as a new item.
There are some people who believe refurbished and used mean the same thing. This is incorrect; there are several differences.
Difference 1: Warranty
All refurbished items come with a warranty. Some used items come with one but most don’t.
Difference 2: Physical condition
Refurbished items are supposed to look exactly like a new item and do most of the time. This usually involves the replacement of things, such as the chassis, faceplates, buttons/knobs, and so on. A used item has had nothing changed on it. It is the same as when it was new, worn and all.
Difference 3: Vendor
It is rare that an OEM will sell anything used. The closest match to this is "off-lease," meaning a corporate customer leased a ton of the whatever-it-is from the OEM, sent them back when the lease expired and then the OEM resells the items. But even this is a rare instance these days because if the items are too old (and therefore cannot be supported directly,) the OEM won’t bother reselling them and instead find other means of liquidating that inventory.
Third-party vendors will sell used items, do so routinely and at times label these items as refurbished when in fact they’re not.
The general rule of thumb is that if you purchase a refurb item direct from an OEM or a large third-party vendor (like NewEgg or TigerDirect,) it is truly refurbished. With smaller vendors you get used. This is especially true if a vendor is selling something labeled as refurbished but there is no warranty and/or is stated to be sold as-is.
Difference 4: Age of item
As noted in #3 above, if there is something in the inventory that is simply too old for an OEM to support, they will find a way to liquidate the inventory otherwise.
If a particular item is still available from the OEM as new, you will find legitimate refurbished versions of it, warranty and all.
If on the other hand the item is discontinued and isn’t available as new any longer, what you will usually find are used versions of that item with no warranty.
The easiest way to check if something is discontinued or not is to go to the OEM’s web site. If you see the item still sold as new, it’s obviously not discontinued. But if it’s not there, it is. Some OEMs are nice enough to tell you this information up front and give you a complete list of what’s discontinued (like Garmin for example.) Others however don’t do this, so you’ll have to go look item-by-item and see for yourself.
Special note on this: There is a period of time right after an item is discontinued where it "rides the fence" for a few months and can still be supported by the OEM, but after that it goes into used-only territory. This all depends on how the OEM handles discontinued product support for newly discontinued items.
Difference 5: Support
This directly relates to #3 and #4 above. Current-model items from the OEM are supported and therefore are available as refurbs. These refurb items have support, so if there’s any issue with it you can call the OEM for help.
Used items have third-party-only support or no support at all. Once you buy it, you’re on your own.
Are refurb items better now compared to before?
Yes. When refurbished items first appeared years ago they were admittedly pretty crappy. This soured a lot of people on the idea of buying anything other than new.
Today the OEMs understand that there is legitimate profit to be made by selling refurbished items. As such, refurb now is a whole lot better compared to yesteryear. These items are good enough to where you get the exact same warranty as you would new. This shows confidence in the refurbished product by the OEM and proves that yes, it will work.
I do recommend people to go refurb instead of new. If the refurbished item has all the features you want, comes with everything the same new product would and is supported by the OEM (which it is,) you can buy with confidence.
Obviously you should exercise common sense when shopping refurbished, because some items are still better new than refurb or "recertified" (I wouldn’t buy a recertified hard drive,) but most of the time the refurb items you buy will serve you just as well as new would.