Wet Socks!

I've been fortunate and have never had trench foot although I've known GIs who have so no exciting stories unfortunately.

As far as prevention goes….

I normally carry two pair of hiking socks and one pair of sleeping socks depending on the anticipated temperatures. I try my best, albeit imperfectly, not to mix being wet and cold. For three season hiking, my feet have been wet for days at a time; I just deal with it and ensure that I can dry them off at night when I go to bed. I do this by keeping a full set of sleep clothes including a dedicated pair of wool socks that stay in my dry bag until it's time to go to bed.

I still hike in waterproofish boots and gaiters in the winter. I try to keep my feet dry from sweat by not overheating them and foot powder.

I always carry one spare pair of socks

Very seldomly use them

Like the time I forgot my gaitors. Then my socks got wet and I went back and forth between my two pairs but it was mostly futile. Walking through wet brush.

Or when I've walked through stream and boots filled with water. Then spent several days of trying to dry one pair while wearing the other. Eventually my boots sort of got dry.

When I wear WPB boots with gaitors that are calf high, breathable nylon, and don't walk through water deeper than boots, I don't use my spare socks.

" I was just curious if anyone has any close calls with frostbite or hypothermia due to all their socks being wet."

Lots of times. It comes especially with winter trekking, whereas in the warmer seasons, the socks are more readily dried hung on the pack. In some areas, like the northern section of the Long Trail in the snow belt in Vermont, rain can be relatively constant for a week or more, which is also a challenge, especially in colder weather in the shoulder seasons. And then there is runout in early spring. The feet feel wet just thinking about it.

1. A pair of Thinsulate booties are carried sealed in the pack and worn only under cover. So at least you can be sure of getting the feet warm after stopping for the day.

2. Next is the third pair of socks in case everything goes wrong.

3. Also, the sox are synthetics that do not absorb water as wool does and dry many times quicker. The ones I like are Lorpen Coolmax Extreme which I reviewed on this site. They are popular with hunters, so can often be found in hunting goods stores.

4. Some kind for fording shoes are good during runout, which for some reason is where I often come up short. Finally made a pair. Problem is that if long distance tramping through marshes, melting snow, streambeds, etc. is required, flimsy fording shoes built or selected for light weight won't hold up. One time, hiking north along the East boundary marshes of Zirkel Wilderness in CO, the deep water seemed to go on forever. Another time, portaging the Mud Pond carry in Maine, found that the 'portage trail' was really just a streambed and a shallow pond that was its source. Back out on the next lake, was numb and shivering badly, and found a campsite just in time. Had to wear the one pair of boots in both situations. But fording shoes are good for saving the boots during short crossings. Good sandals or sneakers may weigh around a pound, though.

5. As Jerry notes, gaiters will keep snow out of the boots/trail shoes, and they help a lot in heavy rain also.

The two sock thing is fine for summer treks, especially in the Rockies and Sierras.
In many other situations, not so much.

> any close calls with frostbite or hypothermia due to all their socks being wet.
That's the one thing we have never had any problems with – and that includes walking in the snow. Yes, even with wet boots. The secret is keeping your legs warm.

Cheers

Carry 2 pairs of light hiking socks and 1 pair of warm sleeping socks.

Having 2 pairs of hiking socks allows you to wash one pair and have it dry out while hiking. Also if you are using non waterproof shoes and it's raining and then stops raining, you have the luxury of changing into dry socks.
If you only have one pair of hiking socks they get real nasty real quick.

Only time my feet have gotten worrisomely cold is when the rest of me was soaking wet in 30s weather. In that case I could have had the driest, warmest socks in the world and still would have been playing chicken with the Grim Reaper if I stopped moving.

Like roger hinted at, your extremities will be ok if the rest of you is warm, barring the most brutal of conditions. I've hiked for a few days straight in a cold creek bed and never had problems. I just made sure to dry my feet off every night. If I hadn't I would have gotten some nasty trench foot, but a few minutes airing out then into a spare pair of sleep only socks seems to do the trick.