Any decent knitting or crochet pattern will give you information on gauge or tension. It will be something along the lines of x number of stitches and y number of rows in a 10cm/4" square with a suggested needle/hook size. Most of us, myself included, have historically focused on the stitch gauge and figured I could just fudge the rest by either lengthening or (more common for me) shortening as needed.
But if we can just fudge it, why is it there?
Turns out, if you're a garment maker, it really does matter in a few key spots of your garment. Do any of these sound familiar? I've done every one of them.
1. Armscye (pronounced Arm's Eye): this is the sleeve opening in the garment and includes all that shaping which happens under the arm and up to the shoulder. Patterns typically give row by row directions for this part of a garment and if your row gauge is off, the armscye will be the wrong size. If your gauge is only off by a little bit, this may not be a big deal. Or you could end up with a garment which clearly doesn't fit well, either too tight to be comfortable, or with too much fabric bunched under the arm. You may get huge 80's puffy sleeves, or a sleeve which simply doesn't fit in that opening.
2. Sleeve Length: Many patterns have the sleeve narrowing from the shoulder to the wrist at a specific rate. The designer has looked at the total length of the sleeve and worked out - according to the row gauge - how frequently that shoulder-to-wrist decrease needs to happen. Have you ever knit a sleeve exactly as written in the pattern and ended up with something laughably long or short? Assuming you worked everything else correctly, row gauge is the culprit.
3. Neckline: This isn't too big a deal on a high neck sweater but a V-neck sweater, which also tends to have row by row instructions, can become a very daring garment if your row gauge is off. Conversely, it may not be nearly the depth of v that you wanted.
Other areas you may see this being an issue are with waist shaping, bust darts or decorative elements ending up in the wrong place, either too high or too low.
The above points pertain to garment making but even if you're committed to things which don't need to 'fit' in the traditional sense (shawls, blankets, scarves etc), row gauge issues can crop up for you too. I've heard endless stories of monster shawls which swallow the wearer and blankets which are almost parachutes.
So what can you do about it?
There are a few things you can try if you're having trouble with row gauge:
1. If your stitch gauge is good, but the issue is with row gauge, try sampling again with the same size needle or hook in different material. For example, if you're off with steel, try bamboo. Square needles vs round will make a difference too. The effect of this will vary and where one person may have a radical change in gauge due to a materials change, you may see nothing. Or you may be astounded.
2. In some cases, your gauge may be exactly to the pattern specs but you may still have issues around flat or straight sections (i.e. knit until piece measures 10cm) which you've carefully measured while on the needles but which still end up way too long (or short). If this is the case, consider the radical step of putting your tape measure away. Instead, go back to your washed sample (you've got one of those right?) and measuring from that, figure out how many rows you need to get the desired length of fabric. Unwashed fabric which is still on the needles won't give you a reliable measurement for your finished product.
3. I've also heard of people having great success with adopting a whole new knitting style. For example, if you're primarily an English knitter, consider learning Continental. Or Portuguese. Or a combination. Of course, this is a big change and there will be a learning curve along with some time needed for you to settle into the new rhythms of the work. But it might be just the thing to fix a long nagging problem.
Do you have other suggestions which have worked for you in the past? Let us know!