If you use long pins to hold your hair, it is extremely recommendable to pull further clothing items over your head very carefully. The resulting mess of hair, sweater and hair accessories is rather difficult to disentangle, especially if your arms are already in the sweater.
And I did use knitting needles, yes, why. I couldn't find anything handier without rummaging in the drawer. But I'm led to wonder where I could find pretty hairpins - maybe I could use the KnitPro Symfonie double point needles in coloured laminated wood?