How to measure to knit baby leg warmers and wool diaper covers

[ShadowFox]

Hi I'm new to this. I've taught myself to knit and have only successfully made two baby hats.
I want to make some wool diaper covers for my son but I'm not sure how much yarn I'll need.

I also want to knit some baby leg warmers for my friends daughters. Do I need them to measure? And how much yarn to use??

I found some patterns but they dont answer these questions.

Thanks a bunch!

P.s whats a good brand of organic wool?

[DeerMother]

For soakers, you will use between 1/2 - 1 skein of yarn. Depending on gauge, stitch pattern and size. Maybe bank on 100+ yards?

I've never made leg warmers, but I know there are patterns on Ravelry.