This is a question I was asked by someone in the Seattle Knitters Guild.
What a great question! I did answer--and was a little surprised by my answer. But because it
is such a good question, I've asked it in many of my classes.
Responses I hear are among the following . . .
1. Working to the wrong gauge--either for the pattern or the yarn.
Good answer! Small differences in gauge can mean big results in fit. If you knit the wrong gauge for the pattern, your finished pieces won't be the size you anticipated.
But knitting the wrong gauge for the fabric is a whole other issue. Sometimes we force a different yarn to the gauge of the pattern, and the fabric is just not right--either too loose or too tight. And when we get the wrong gauge for the fabric, there's not much we can do to fix it.
2. Choosing the wrong yarn for the project.
This is kinda related to the last point above: we pick a yarn that won't get the right gauge or won't produce an appropriate fabric for the garment. And producing a fabric that is not quite right is a much more difficult problem to anticipate. I've done this many times (and have a pile of garments knit in great yarns that need to be ripped out): the yarn was too stiff or too drapey and didn't give the right result for the project.
3. Not buying enough yarn
It has been a fascinating discovery to me that if you knit the piece in a different yarn you will not use the same amount of yarn! I think this so very counter-intuitive--that you can knit a second version of something . . . in the same size, to the same gauge, over the same number of stitches and rows, but in a stiffer yarn . . . and you will use more yarn!
4. Choosing the wrong style.
We knit something that looks fabulous in the photo but really bad on us! Maybe this speaks to the optimism of knitters?
Okay, so that's a list of common responses, all very good, all very thoughtful, all very appropriate. But they weren't my answer.
What would yours be?
I'll tell you mine in a couple of days . . . .