A typical off the shelf survival in a tin kit can contain a pack of sugar, book of matches, one razor blade, stick of gum, one tea bag, one beef bouillon cube, safety pin, whistle, one fishhook, stub of pencil with no eraser, button compass, piece of paper and a Tootsie roll.
The kits do vary of course, so in other tin survival kits you may find in addition to what has been listed an alcohol wipe, ointment for burns or abrasions, fishing line and hooks, and a small mirror, or the inside of the lid can be used as a signaling device in some cases. You can also purchases specific kits such as a survival fishing kits.
The size is small, typically the size of an Altoids Tin. Space is limited, and in the absence of other gear or materials certain kits could mean the difference between surviving and not. The tins are small enough to put in your pocket, but you should not consider the tins the end all to survival, consider them instead a backup or the go to material in a desperate situation when nothing else is available.
Should you plan a day hike, hunting, or camping trip and only consider carrying a survival tin. No you should not. The tins should be in addition to your typical load out for camping, hiking, hunting or when just enjoying nature.
As stated earlier in the absence of anything else the material can be used, but unless you have built your own survival tin and have tested the products under field conditions you have no idea of the quality of the off the shelf products. If you have the right materials in your survival tin they could be used to survive until rescued.
What Is Needed
If nothing else buy the tins for the container, or purchase some Altoids, enjoy until empty and repurpose the container.
Some of what is included in the off the shelf tins are comfort items. A tea bag, pack of sugar, or salt, beef bouillon, and gum while nice to have are not needed for your immediate survival.
Instead of a book of matches or a small cylinder of so-called waterproof matches replace with a magnesium stick and/or a quality Ferro rod. You probably do not need a pencil stub for your immediate survival. You are not likely to be in a Robinson Caruso situation so leaving notes in a bottle is not needed. Your goal is to survive and to help rescuers find you.
Fire is needed for warmth and for signaling, so quality materials for fire is a must for any survival tin. Add some fire tinder and make sure it is protected from moisture and/or add some wet fire.
Fishhooks are essential in some situations but without quality line they are not much use in the short-term. The few feet of line included in some tins is not adequate and the line takes up space, so instead add a Bic lighter as backup or add a small multi-tool instead.
You need a compass and quality Ziploc bags for water collection and to carry water if needed. A quality whistle is needed for signaling and you can add some folded up aluminum foil which has multiple uses, and signaling for help is among the uses.
Anti-bacterial wipes can be used to prevent infections, so have at least one packet along with several alcohol wipes, for hand sanitation or fire starting, and include several bandages.
A good razor blade can be used for various tasks and when used with the pliers on a multi tool you have a skinning blade. Grip the blade with the pliers to perform tasks to reduce the chances of slicing your hands or fingers. They do not take up much space so add several and make sure they are the ones that have the grip strip, in other words they are not blades that are typically used in utility knives. Any blade you have is a good blade in a survival situation however.
Cordage is important but how much can you stuff in a tin, is it enough to be of any practical use. Any cordage is good cordage, but it does take up space so consider other ways of carrying cordage during the normal course of a day. Consider boot laces, Paracord bracelets, or belts made from Cordage instead, and save the space for other items. You can get creative and wrap the entire tin in Paracord but at some point you will have defeated the purpose of the tin which is a small unobtrusive tin that can be easily carried.
The tin should be there when all else has failed, but you should not consider it the first line of defense. Pack one every time or carry one everyday as part of your EDC. Properly preparing to become lost is your best defense however when planning a hiking, hunting or camping trip. Anyone can get lost but not everyone can survive the ordeal.