What is the most useful length of circular needles?

What is the most useful length of circular nee

So you don't need a circular needle, but you want to use them because they are easier to handle. What length should you get. In general the most useful size to purchase would be 24" or 32".

I know we have readers that only crochet, I haven't forgotten. The most useful sizes of crochet hooks are G, 7, and H.