You must keep your feet healthy if you want to continue walking long distances.
Ill fitting boots
Worn out Sock
Wet and/or dirty Socks
Wetness
Wetness in your boots will lead to softening of your skin and can lead to severe fungal infections, nerve damage and serious injury. This can mostly be avoided by drying out your feet and changing your socks.
Your feet need to air out at night. Never sleep with your boots on, unless your are so cold that you need your boots to keep your feet from freezing.
The best way to keep your feet dry is to avoid getting them wet in the first place. Avoid walking or standing in water. Even waterproof boots will get wet if you get water or snow over the top of them.
You should have at least 3 pairs of socks to cycle through. Wash, dry and wear them and cycle through them as needed. In wet conditions, you may need to change socks 3 times a day.
When at camp, remove wet or moist socks and allow them to dry. Put on dry socks and boots before your hike out.
If you have a limited supply of socks, wash them when you can and leave them out to dry.
A campfire is great for drying out stuff, but be careful. It is easy to burn your gear if the flames get too hot or too close. If you can hold your hand in a area for 10 seconds, it is probably safe to dry clothing. Clotheslines should be placed 5 feet or more from a fire.
If you are on the move, you can dry out your sock on the outside of your backpack, on your belt or under your jacket.