Starting a row with slip stitch vs. knitting the stitch

Some patterns say “sl” first stitch and knit (or purl) row. Some just say knit next row or purl next row or st st, etc. without any specific instruction with regard to that first stitch. What is the difference in slipping the first stitch vs. knitting or purling the first stitch?

When the first stitch is slipped it creates a chain edge which looks very nice on something like a scarf. If you just knit (or purl) the edge has a little knot. It’s often just personal choice.

One thing though…whichever you choose to do be consistent because it will be obvious if forget to slip a row or slip a row when you’re knitting.

Slip the first stitch purlwise with the yarn in front and knit the last stitch OR Slip the first stitch knitwise with the yarn in the back and purl the last stitch.