Interchangeable Knitting Needles are a Popular Gift for Knitters
You did the right thing. You asked the obsessed knitter in your life what they wanted as a gift. You may be kicking yourself now because they told you they wanted "Interchangeable Knitting Needles" and you have no idea what those might be.
Simple, they are a set of knitting needles that contain every available size that can be configured to accomodate any knitting project.
Here are a couple of sets:
What the heck is a set of interchangeable knitting needles?
Interchangeable Knitting Needles are a set of circular knitting needles with removeable needle tips that allow knitters to have every size knitting needle. The needle tips are connected to a circular needle cable, usually available in multiple lengths to accomodate different project types. The small cables are for smaller projects like hats, while the medium sizes might be for sweaters and the extra large ones used for blankets. But it doesn't matter so much to you what these needles are used for as much as how to choose and purchase a set.
You don't need to become an expert. The main thing you should know is that the Interchangeable Knitting Needle set is the premium knitting gift. It is the most expensive tool set that a knitter can have and it is a luxury to own. There are some sets that are less expensive and just as effective. That said there are many sets available on the market and it will save you a lot of time if you take a little time to figure out a few things:
What You Need to Know about Interchangeable Knitting Needle sets:
1) Which set does the knitter in your life want?
Just ask directly. If you're not a knitter there's no way that the knitter in your life will expect you to magically know which set they want. Ask them. AND THEN WRITE IT DOWN. You don't want to be trying to figure out whether your knitter said "Knitter's Pride" or "Knit Picks".
2) What if they didn't say they wanted interchangeable knitting needles but you just wanted to get the best knitting needles available?
Do not pass go, do not collect $200, just go straight to Addi Clicks. They are the BMW's of interchangeable knitting needles. Get the extra long tip lace set and your knitter will squee almost as loud as that lady in that deli scene in When Harry Met Sally. Seriously, if any knitter opens these up as a gift they might drool with anticipation figuring out what they're going to knit with them.
3) What if you don't want to spend nearly $200 on knitting needles, but still want to get a quality set of interchangeable knitting needles? What is the best quality interchangeable knitting needle set for the money?
There are two options: heh heh, Knit Picks Options, or Knitter's Pride Symphonie. Both are made by the same manufacturer. It's just a matter of whether you think the knitter in your life will prefer a solid color wooden needle tip or a multicolored wooden needle tip.
4) What about all those other sets of interchangeable knitting needles?
If you want to go into an in-depth analysis of interchangeable knitting needles, check out Knit Luck's Interchangeable Knitting Needle Guide. They've been slowly evaluating all of the interchangeable knitting needle sets. They've only done 7 or 8 sets, but that's because they're expensive and difficult to test out without spending a mint.