I swear I almost used a lifeline on a garter stitch shawl the other day. It has 245 stitches and I kept dropping stitches and not being able to find out from where. Better solutions were found, but I will definitely consider using a lifeline on projects other than lace.
I started using life lines after making the Forest Canopy Shawl. Susan Lawrence was my first lace pattern. I wish I could tell you how many times I had to take down because I lost my place or drop a stitch. Life lines have save me. Donna