This is a easy way to fix a zipper without replace it. Is really fast too.
It work when the zipper pull can't close the zipper together anymore.
I don't really like to replace zipper because they always come out a little bit wavy when I do.
You can save a jacket, a tent, a sleeping bag and many other item.
You need only some pliers.
But if the zipper pull is really destroy or is made in plastic you need a NEW ONE OF THE SAME SIZE.
YOU CAN FIND IT IN ANOTHER OLD JACKET. Or you can buy one online for really cheap.
Remove the little iron teeth of the really top of the zipper (on the same side of the jacket where the zipper puller is)
Remove zipper pull.
You can probably see that is all distorted.
(ONLY FOR IRON ZIPPERS)
Whit the pliers close the two sides of the zipper pull, try to make it look like the original shape again.
If your zipper pull is not too worn out you can try to close it directly on the zipper, without remove it.
(if it is made out of plastic, if it is too bended or it break doing this you need to find another one of the same size).