My experience has been a liner will not prevent a blister. If you are getting a blister you need to either change the way you lace your boot or get new boots.
I use to run the blue redhead poly liners. I than read an article about how adding more layers to your feet, although meant to wick sweat, in fact just makes it harder to do so. Thus, I started to just wear pure wool socks and have never had an issue, assuming your boot fits correctly.
I agree with /\/\, used to use liners but it's a second layer on the feet and I finally switched to just good wool socks and much better. More miles and less problems. I know lots of guys say to use liners and they like them so worth a try if you haven't tried them but it may not be the best for you. I still got blisters with liners and the second layer felt weird the majority of the time, sometimes it was fine though....?
I have used them for about 5 years now. I have not gotten a blister since. A small hotspot but that's all I can remember.
I have mostly used a super thin black liner sock from smart wool. No problems. This for no particular reason other then a recommendation from AKtrout here on this site I tried the Arma liners. They are pretty awesome as well but pricey.
I've been using some form of poly liner socks for decades under wool socks, and have never gotten a blister no matter what boots I used. I can't say for sure that they "prevent" blisters, but I'd say that they certainly don't create them for me. And they make my feet much more comfortable. My merino socks are always wet at the end of a day when I take them off, but my liners feel dry and they stay on for sleeping. Throw the merino socks back on in the morning, and do it all over again.
No sock liners for me as they caused problems rather than prevented them. Merino-wool socks year round. If you're getting blisters, something is not fitting correctly.
I would suggest using leukotape on the area where hotspots or blisters occur until you can find properly-fitting boots. That will avoid blisters.
I used them for years but have ditched them in recent years. I would look at them as more of a specific solution rather than a general one. Overall, you need to get your boot fit + insole + sock combination dialed in appropriately and you should get blisters (assuming you spend enough time on your feet and your boots are broken in). “Sock liners will keep you from getting blisters” excludes too many other factors and if you are going to use them, you may have to adjust boot size or your outer sock.
Sock liners greatly reduced blistering for my feet, so I wholeheartedly recommend them. I mostly use Cabela's branded ones...just make sure they fit well. If they're loose they can't really do what they're supposed to.
I use compression socks, instead of just liners socks. They help to minimize swelling and I found that more helpful then just adding liner socks... but after 2 broken tibial plateaus, I might get more swelling then most.
I always have problems with getting blisters between my toes so this year I tried the Injinji merino wool liners. I used them and ran a pair of thin darn tough over the top. 5 days and 55 miles later I took off my socks for the first time and I didn't have any problems. I was really impressed with the way they worked.