Does anyone know how often Dr. Martens come out with new colors of their 20eye boots? I'm tempted again with the purple ones, but would really like blue. I haven't been around watching them long enough to know if it's rare for them to come out with new colors or not? The grey would have been a great neutral for me, but I didn't like the shade and I'm not sure how neutral the purple would be for me, although I'm loving them on everyone. Anyway, I just thought I'd ask if anyone knew. TIA!