Both. I have clip less exauster 'winter' boots. They are ok on their own. I added felt insoles, and glued some on the inside of the tongue of the boot. I wear good quality wool/hollofil socks and my feet are fine to -5C. Below that I use Louis Garneau neoprene booties if it is sloppy out, or some toesport booties when it is dry. When it gets below -10 and I am out for longer than 45 minutes I add toe warmers. Toasty toes are great, and I found that if I place them in a ziplock bag after the ride I can use them on the way home with no 'loss' of heat from them.