Yes I agree with the above posts. More info about where you live and your coop setup would be helpful. Also, on what chicken breeds you have that are experiencing the problem.
It is not something that you want to do if you have another option, because hens have combs for a reason. They help them cool down in the summer and regulate their blood circulation.
We live in North Central PA, where our winters are very cold and our summers are very hot. This last winter was our first winter having grown chickens and it was tough. The roosters got frostbite on their combs pretty badly. We were debating dubbing them, but after starting a thread on here, ultimately decided to let the winter take its course and see how they would be in the spring.
All of them are ok. Some of them lost the very tips of their combs, because the winter "naturally dubbed" them. They looked horrible in the winter, their combs were all black and blue, and bloody. It was a horrific sight. However, we believe they will be stronger because of it this winter. And now, because it is mid summer, we are glad we did not dub them! Their combs help them to regulate their body temp so that they don't get too hot.
Our hens on the other hand, never had that bad of a frostbite problem so far. None of them lost any of their combs, and you could never even tell they had a problem at all.
So throughout the winter, we spent every single night rubbing olive and/or coconut oil on their combs. This helps protect them from the harsh conditions.
With frostbite, it's not actually cold you need to worry about. It's moisture.
So the oil actually blocks the moisture from their combs, hence protecting them a little more.
Some of our roosters got frostbite still, but this saved us from a lot of problems. I would definitely recommend looking into rubbing oil on their combs.
I would not recommend dubbing unless it is something you are absolutely certain is the best thing to do for them, especially if they are hens (hens have smaller combs).
EDITED TO ADD: I see you added where you live in one of the above posts.