If you have about 10 of these, you can have fire starting ability for life.
Having a lifetime supply of ammo is really important. You want to make sure you have the ability to protect yourself for a very long time. It's really hard to gauge exactly how much ammo you will need. You can get a rough estimate of how much ammo you will need for hunting, but getting an estimate of how much ammo you'll need for gunfights is more difficult. All I can say is, the more isolated and hidden you plan on being, the less ammo you'll need. If you plan on being less hidden and closer to populated areas, the more ammo you'll need. Remember, some real bad guys are going to rise to power real quick. If you plan on engaging them, make sure to have lots of firepower on your side.
Because chapped lips suck. I'm not sure if petroleum jelly has a shelf life of 50 years, but it's a very long shelf life. Whenever it goes bad, though, you can use animal fats and oils.
I would imagine about 6 per person would essentially amount to a lifetime supply of these, so this one's not too difficult.
A good toothbrush can last 5 years. So, about 10 would amount to a lifetime supply for most. Easy. A good idea would be to stock up even more of these and you will have wonderful bargaining items. Toothbrushes can make you wealthy later :)
Most of the junk we eat now has lots of salt and sodium in it, so we don't realize how important it is when we don't have it. If kept dry, salt can last a very very long time. It's also cheap. Getting a lifetime supply wouldn't be too hard, but it will take up a sizeable volume. Perhaps you can look into buying salt blocks.
After the SHTF, communication will be very important. Written notes and letters will be one of the most important forms of communication. Paper can be used for simple notes, such as "Went hunting. Be back by dusk on wednesday." You can write letters to neighbors, send messages to people whom you want to extend your friendship, and send correspondence to other power players in the region. You can make sheets of the items you are selling and trading. You can keep inventory of food and items. You can print out pages of the most important survival information and pass them out to others. You can print out pages of advanced survival information and sell them. Years after the collapse, you can print the news and have a publication of sorts. You can record events and keep a journal. If your writings last, they will become a very important historical work. You can take notes of the information you hear over the radio, or jot down things you need to say over the radio. So, considering all this, it is important to try and have a computer and printer, or at least a typewriter, and pens or pencils.
Dental floss can be used multiple times before throwing it away and it doesn't take up too much room and it's cheap, so it shouldn't be too hard to get a lifetime supply. However, if you know of plants that have fibers you can use instead, maybe there's no reason for a lifetime supply.
Beards are boss, but every now and then you might want that smooth shave again. Some razors these days are really expensive, but some are cheap. If you opt for the old school single blad razors, you can save money and they don't take up much room at all. But to be honest, no matter how many razors I stock up, I'm probably gonna end up giving them away to women, just cuz I feel like they would value them more than me.
Your main method of catching fish probably shouldn't be with fishing line and hook. Other methods are more efficient. However, you should still have hooks, line, sinkers, bobbers, and some bait for certain circumstances, like when you are just starting out or you are travelling to other areas and need to catch some fish for dinner.
Fishing string also has other uses, like trip wire alarms.
Pencil Lead (for mechanical pencils)
You're going to want to have something to write with forever. I think mechanical pencil lead is perhaps the best way to do that. Estimate how much you will need for life, then double it! :)
I would have gone with Gorilla Tape, but it's more expensive, so load up on this stuff.
Dry Erase Markers and/or Chalk
Having a white board or chalkboard in your community can have so many important uses, from education to planning to message boards. I like whiteboards better, but I have my doubts about the shelf life of dry erase markers. If you want to try storing dry erase markers, I recommend vacuum sealing them. But you should probably get a chalkboard and lots of chalk too. I think chalk can store for many decades.
If society collapses quickly, you can expect 90% of the population to die, so a lot of clothes will be available for the taking. You will probably be able to acquire clothes from raids on unoccupied homes or through trade networks. Some guys will make a business out of stocking up on the clothes of the dead people and trading them. However, with at least shoes, underwear, and socks, I wouldn't want to rely on that, so I will get a lifetime supply of those. Nice shoes will be important. A good pair of boots can last 10 years, so 5 pairs or so will be good.
Because I'm probably not gonna be interested in itchy wool underwear down the road.
Good socks are important. I think it's a good plan to bite the bullet and buy a lifetime supply.
Obviously, these aren't the only items I will have. These are just the only items that get burned through with regular use that I will keep a lifetime supply of. What is missing from this list? Don't say toilet paper or I'll pistol whip you.