[COLOR=“Blue”]Hello.
I am starting a lap blanket that calls for US8 size needles, cast on stitches 180. I am seeing needes US8 16" and 24". Which one should I buy (16 or 24) ? Secondly, can I use either one for smaller patterns in the future as long as it calles for US8 size ?
Thank you.[/COLOR]
:knitting:
For the blanket I suggest the longer needles so the stitches don’t fall off as easily
you don’t have to cover the entire needle in stitches in order to use the needles, so you can definately use them for future projects.
For a blanket? I’d go with 32. After you’re done you can learn magic loop and use it for pullovers, hats, even socks if you want a heavier weight pair. 
The 16" are mostly for hats, 24" can be used for a lot of things including a lap blanket, and even a hat if you use a version of the magic loop technique. But 29 or 32" ones are a pretty versatile size, able to be used for small items or larger. Buy what’s most readily available to you.