A lifeline is a piece of thread passed through all the stitches sitting on a needle once you have completed a row. It's purpose is to provide a point where everything is correct and, should a mistake be made later on in the project, the work can easily be taken back to the lifeline, knowing that all stitches are secured.
You will need:
Scrap yarn & a wool needle.
Putting in a Lifeline:
Use your wool needle and a piece of thread/scrap yarn (I'd recommend a contrasting colour) and pass through all the stitches on your needle.
Do not secure the lifeline to the work by weaving the ends in or knotting it. When knitting the next row ignore the lifeline and knit the working stitches around the needle only.
I add multiple lifelines as I work through a lace project.
If you need to use your lifeline, simply frog/unravel back to the lifeline. As all the stitches are secured on the lifeline, you can slip them back on to your needle and start that section again.
Once your project is complete you can gently pull on one end of the lifeline, and it will slide out from between the stitches.
