Like Roger, I use dailies, for the same reasons and with the same results. Like him, I put them in my sleeping bag every night if anticipating below freezing weather. The worst I have ever experienced is that storing them in odd orientations to the horizontal occasionally results in a lens being "inside out". I always hold them up on my finger tip to check for this and flip them "outside out" if necessary before inserting. They are a lot less hassle than lenses that require a soaking solution and more sanitary, IMO. OTOH, on longer trips they can potentially take up more space in your pack, depending on the number of days and the size of your bottle of soaking solution. My opthalmologist told me that the lenses you can wear for a month have potential infection issues, worth thinking about in the backcountry, and are not appropriate for people susceptible to "dry eyes", a situation that afflicts more people as they age. Worth checking with an expert, I should think.