There are some errors which you must fix, such as when you are doing a project on circular needles that calls for you to join it after the first row i.e. a hat. If you accidentally twist that first row, your project will not lie flat, and wearing a hat with a twist in it would be mighty uncomfortable. Therefore, you must undo your work to back to first row, make sure it is not twisted, and re-join and carry on.
Another type of error you must fix is a dropped stitch. If you are working a pattern, such as a lace, your count will be off, so you will soon notice this and have to fix it. It may mean undoing several stitches, but to get yourself back on track it is worth the time. If you count at the end of every row, and your number is off, you only have to figure out where you went wrong on that one row. The same goes for crocheting. If you make a mistake in your shells, for example, they won’t lie properly on top of one another and it will look off-kilter.
The next type of error is one you can choose to fix or not. This would be something like a twisted stitch or a skipped stitch. If it doesn’t affect the look of the row, and if it doesn’t bother you, then let it go.
Some people are perfectionists, and knowing that a stitch is wrong, it will bug them to the point that it drives them crazy. They simple cannot live with that imperfection. In that case, it is better to fix it, no matter how much effort it takes, so that they have peace of mind.
Also, you have to take into consideration where this project is going. If it is for yourself, and every time you wear that scarf, and you remember that flaw, it is better to fix it. On the other hand, if you are donating it to a person who is more interested in warmth than perfection, then let it go.
As well, if you are being paid to make a professional looking item, you want it to be close to perfection as possible.
“The Amish people intentionally sew at least one error into their beautiful quilts…Their thinking is nothing made by a human being should be perfect”.
After all, this is a hand-made item, so it will never be as perfect as a machine made item. But, you don’t want it to look like it was hand-made by someone who didn’t care how it looked either.