Submitted by Rusty Rodke
When my niece deployed to Iraq, I asked her if there was any gear she needed. She said that she was sleeping in her sleeping bag every night and, while she could send it off to be cleaned, it was awkward and cold to do without it for the three days it took to get it back. By having a couple of liners, she could wash one locally while sleeping in the other. Silk, fleece or polypro liners would add 10 to 15 degrees of warmth, but cotton was more comfortable in the heat and could be used by itself on really warm nights. REI has a good selection of liners.