I'm really new to knitting and the one thing I can't seem to get my head around is when you are knitting a blanket, what do you do when the edge you are working on is getting longer than the needles you have?
That's when it's time to use Circular Needles. You can use them to knit in the round and when you need longer needles.
Yes circular needles can be used like straights when you have a lot of stitches, they're not just for knitting in the round.
I use circulars to knit my blankets. I use the same pattern as a traditional dishcloth only much much larger of course. I've made this pattern as small as a baby blanket and large enough to fit on twin size bed. You could also make strips or squares using your smaller needles and then just join them together.