The split end is to healthy hair what kryptonite is to Superman, and despite our longing for long, Rapunzel hair, there's only one way to deal with them: chop them off. Yes, that's right, you need to cut your split ends loose and move on, however harsh that may sound (sniff).
What causes split ends?
The ends of your hair are the oldest and have thus been subjected to more heat styling and other stressors than the rest of your mane. This means they're more likely to become dry and brittle. Once the strands are that damaged and vulnerable, they start to split.
Left unchecked, the split end will travel further up the shaft. The only way to stop the damage in its tracks is to trim the hair in question or risk losing more length than you anticipated when you finally make it to the salon.
Why can't split ends be fixed?
Even though you can reduce the appearance of split ends with a smorgasbord of different products and treatments, you can't actually undo the splitting process or successfully bind the hair shaft back together long term. Essentially, your strands aren't capable of repairing themselves and no product can recreate a healthy, natural hair shaft.
How can split ends be prevented?
Avoiding major stressors like daily heat styling, using heat protectants, and maintaining well-conditioned tresses will all help reduce your chances of split ends, but sometimes they just happen. Getting regular trims will catch them early, ensuring you get to keep as much length as possible in the long run.
How often you need to to get a trim depends on your hair type and cut, but generally speaking it should be about every 4-6 weeks, or every 6-8 weeks for longer manes.