I don't like to purl with this size of needle. At all. When I get the sleeve knitted and it's time to do the lower ribbing, I'll switch to double points. I need more needle to grip or something when I purl and these little circulars just don't work. This means that I will have used three different needle types/sets on this sleeve when I get it done: the long circular I used for the short row section, the 9 inch circular, and the double point set.
I remember when I first started knitting and I thought one type of needle (in all the sizes) would work. Now I know that not only do I need lots of different types of needles, I need them in several different materials too because different yarns work better on different needles. Of course I also need lots of different needles so I can work on several different projects at once. Is there ever a point where you have all the needles you need?