I've been wearing liners to fix a fit issue with a pair of boots that I bought 2 weeks before sheep season... 4 years ago. Boots were a little loose with the thickest socks I could find, and liners were the only option.
Every year, my buddy with custom molded liners on his plastic Koflach boots has blister issues. In fact, his entire foot looks like hamburger. I've never had a blister, in those 4 years. My liners are cheap poly ones made by LaCrosse, Fox River, and I'm sure a couple other makers.
