There are fewer more well known, yet less utilized, items among 'packers than the lowly plastic freezer bag! That's "plastic FREEZER bag"! Plastic sandwich bags are not up to the task.
Probably because they are not "durable", in the strictest sense, but at pennies per bag, they don't have to be! And of course, they are ultralight and don't take up any space. Even if the skies are clear and sunny, I routinely organize my clothes and gear into these plastic bags!
To help keep things organized, one of the many mod's I made to my pack is I canabalized a shoe caddy (the kind of thing you may find of the inside of a closet door). I then sewed two sets of those pockets to the inside of my pack (one each to the left and right side). Then I just stuff the plastic bags/kits into those pockets. This is an important step, after all, while the bags can keep items together, they can still shift around and settle to the bottom! Those pockets keep that from happening.
Obviously, plastic bags help keep your things organized and waterproof, which are not small considerations, but that goes double for my food rations.
I pack, or repackage, my meals into small individual bags, then pack several day's worth of meals into a large plastic freezer bag. I can put SIX of these large bags into my Ursack.
Then I strap my Ursack to the outside/bottom of my pack (NEVER inside my pack). What about puctures or wear? True, I often sit with my pack resting on a rock/log, and this habit COULD cause wear-and-tear problems later, that's why I sewed an extra piece of fabric to the outside/bottom half of my Ursack, so any wear-and-tear will be on the fabric, NOT my Ursack. Punctures? I've never had a puncture, that I'm aware of, however, it is possible.
While there is a limit to how much food I can carry (about 3 weeks), some will note I will stay out for a month (maybe longer). How? That's where backcountry skill (and chance) comes in! I fish, trap, snare small animals, which can significantly extend my rations (and make the outing FAR more enjoyable and interesting).
To clean/prepare my wild food, I use a plastic cutting board. It's only a few millimeters thick, but is SUPER tough, light, and takes no room, so, I put that on the inside/bottom of my Ursack, where my whole pack would be resting. Punctures? Eliminated!
About once a week, or sooner, I like to wash my clothes. To do this, I use two large freezer bags (one inside the other, of course). For soap, I find 'shampoo and body wash' does just fine for ANY/ALL of my soap needs.
I start by drizzling some soap along the inside of the inner bag, then lay the bag flat and smoosh the soap around (to distribute the soap better). Then I drop in enough clothes to fill the bag about half way. Now I add about 2 liters of water, leaving just a little air inside. Then I seal both bags, and start agitating (shaking, rolling, rubbing, etc.) You'll know you've got it right when the water becomes murky/dirty almost immediately.
If I'm drenched with sweat when I get to camp, after I wash up, this is one of the first things I try to do, then I'll either finish the wash-rinse cycles that night, or I'll let the clothes soak until morning. THEN I'll see to dinner... of course, it doesn't always work out that way.
I should note here, that REI does have off-the-shelf items that are equivalent: a laundry bag that kind of looks like a dry bag (but it it's more-or-less a 'one trick poney') and liquid soap, good for everything (but it's kind of expensive).
SURE there are backpacking pillows, and I get it, it's a nice little luxury, and may help you sleep better (I normally don't use pillows on the trail). But plastic freezer bags can fill this need, too.
Using a large freezer bag, catch some air inside, zip closed most of the way, then adjust the air to your comfort, and seal. For good measure, to keep it closed and from deflating, you can double-bag, seal it closed with tape, or put it inside a stuff sack, etc.
"Freezer Bag Cooking" IS a thing (Google it). Just put your meal in a small bag, pour in hot water, and seal. DEFINITELY have a way to insulate the meal well. Use a scarf, clothing, a mylar blanket or bivy works well, but freezer bag aficionados normally make a "cozy", made from materials that insulate well.
Obviously, perhaps the biggest advantage is you may be able to eliminate your mess kit AND stove set-ups!! Even "cold-soaking" is possible (if you can assure the bag will not open). All of which means a considerable savings of weight and bulk (not to mention, NO CLEAN UP!)
Yep! I've actually never tried this myself, but some of my survivalist friends SWEAR by it.
Provided it's sunny, put water into a bag, and twist it closed so the water forms a round, clear bubble. Then using it like a magnifying glass, focus the sun into a point onto your tinder. For best results, use a brand new bag, medium or large would be better still.
Minor cuts and scrapes are not unusual in the out-back, but the backcountry is a dirty place. Even mosquito bites can become ulcerated if not cleaned. So one item included in many kits is an irrigation syringe, used to squirt water into the wound to help clean it. The problem is it's a one trick pony and it takes considerable space in what should be a fairly small kit. So what I did, is I cut away all but the most essential part of the syringe, the tip/point.
If I should need wound irrigation, I get a small bag and push the syringe point into one corner, fill and seal. VOILA, an irrigation syringe.
These are just some of the lesser known uses, I'm sure others may add their own.
Ya, I know, I like to fold my map so the most perinant areas show through the plastic. And although I keep my paper map in a small bag, that's just to keep it with my compass. Besides, all my paper maps are [printed] on waterproof paper.
BTW, REI also sells a liquid you can brush onto your paper maps to MAKE them waterproof.
@SurvivalGal I didn't know they sold a liquid protector - I'll check it out. I've used my vacuum sealer in the past to make my printed maps waterproof but those are single-use so if I no longer need the map, I've added plastic to the landfill (in theory because I actually keep them in a file folder, "just in case")
My kids have multiple bottles of Modge Podge - I wonder how that would work? (I'll have to try that this weekend)
KEEPING FEET DRY (?)
We've talked about this before in reference to water crossings.
Ya, you COULD use large plastic bags to help keep your feet dry (some people do), although it'll only work in situations with ankle-deep water (at best), or if your boots leak, etc., and will really only help if you are essentially 'zig-zaging' across little streams.
Otherwise, the condensation will keep your feet from drying, so you'll want to remove them after a while.
No matter WHAT kind of plastic bag you use, the problem is not water getting through the bag, it's water getting OVER the bag (over the top).
You can try to tape it closed, and that may work for a while, or tie something around it, but it would have to be tight so you'll cut the circulation.
No, the BEST time to use plastic bags to keep your feet and/or socks dry is in camp (then take them off before you go to sleep).
Otherwise, get some guts and embrace the suck!