Pattern gauge: With appropriate yarn and needles, Seed Stitch is approx. 9 rows/inch and the Garter Stitch border is approx. 8 rows/inch
Based on this, if you have correct gauge your knit scarf will be almost 99" long, including the border.
I'll be back to fill in the 'official' crochet gauge.
What to do if this is too long
If this length is too long for your liking, there are lots of things you can do!
- Eliminate the border (that should cut off about 8 inches)
Do one row for each day instead of two (but make sure your scarf isn't TOO short!)
Are you planning any length modifications?