If you are camping in cold conditions, you may or may not have snow. The primary thing to remember is if you can keep 100% dry, you can easily stay warm with some good layers. As soon as you start getting significantly wet, it is the beginning of the end. The wetness might come from stepping in a slush puddle, or it might come from sweat.
One way around this is to plan out what is going to get wet first, e.g. socks, and have a dry change available.
The next trick is this. Once your socks get wet, and once you have changed to dry ones, how are you going to dry out the original ones? There are several ways, mostly drying them over an open fire, and that risks them burning up.
If you sleep on your back, put the damp socks on your chest and sleep in your normal sleeping bag. In the morning, they will be all or mostly dry from your body heat.