Proper Use of Vapor Barrier Socks

Over the weekend I had good results using a vapor barrier (bread bags in my case) in warmer weather (low 30s and up), at least until one of them developed a hole. However, I was just reviewing their proper use online, and I see that it's recommended to use VBLs under your socks whereas I was using them over my socks. My thinking was that, yes, I was going to have wet feet from perspiration, but at least it would be warm wet feet. On the other hand, without the VBL, or with the VBL under my insulation, the cold water from the marsh I was hiking through would carry away all the heat very quickly, and I'd be left with wet and cold feet. It seems to have worked out for me the way I imagined, but perhaps it's different in colder weather? Maybe whoever came up with the VBL concept didn't really intend for them to be used in a wet environment with light shoes? Does anyone have any thoughts to add on this based on theoretical or practical experience?

I only use a VBL at night, when the temps are approaching or below freezing. I never use it next to my skin but put a layer of synthetic base layer in between.

On the other hand, I've often used the plastic bags over the socks in cold wet conditions. That's not so much a VBL as keeping socks and feet dry. I suspect all-day use is not a good idea, because socks will become saturated with body moisture.

IIUC VBs are ideally used in very cold (e.g., below 20F) dry conditions where sweat is less of an issue. I don't think you necessarily used them incorrectly, but the typical reason for the whole bread-bag thing is to keep soaked shoes from soaking socks and leading to freezing feet. It's what mom did before sending us out to play in the (always slushy) snow when we were kids.

For trail travel I'd wear a thin inner sock, then the VBL then an outer sock. But as I never hike in the super-cold I've not done this myself. Generally, I prefer WPB gaiters. (Have use a VB sleeping bag liner.)

I've used neoprene socks and Goretex socks cycling, and they're a huge help. It's hard to keep feet warm on a bike.

Based on what you guys are telling me, I'm thinking there's five distinct situations which call for distinct solutions:

1) Cool (not cold) wet weather - bread bags over socks.
2) Cool dry weather - no barrier necessary
2) Cold dry weather - VBL under socks (over thin base).
3) Warm/hot weather, wet or dry - no barrier, just deal with wet feet.
4) Cold wet weather - I don't know, buy boots maybe?

Seems like a good summary. The most miserable weather is usually between 30-40F, give or take, and traveling over snow when it's raining is my least favorite thing to do. How the heck did I ever take to hiking in the Northwest?

Waterproof boots/shoes and lots of sock changes isn't a bad way to go. An unfortunate coincidence is that I blister most easily when my feet are wet, so getting them dry at least a couple times/day is really important.