Curl breakage is very common amongst those with natural hair. If you're noticing your curls are breaking off and you're having a hard time achieving length, there could be a few factors involved. For example, curl breakage is often caused by dehydration, lack of protein, or damage from heat or chemical styling.
How can I treat breakage?
In order to treat breakage you have to first understand it.
Your curls need tons of moisture to thrive. Dehydrated curls lose elasticity, making it prone to snapping when handled. In order to keep curls moisturized, utilize water in your styling a minimum of once a week. You can do this by spritzing your curls with water or leave in conditioner. You can also create your own water/oil mixture to add even more hydration. Remember to seal your strands with shea butter. Additionally, make sure to keep up your own water intake so you're hydrated from the inside out.
Heat and chemical styling:
If you blow your curls straight, use a curling iron to touch them up, color or relax them, odds are they're going to take some damage. If you must use heat on your curls, make sure you're utilizing regular deep conditioners with protein and moisture, as well as using protective sprays. The same goes for chemical treatments. Try to avoid lightening or relaxing damaged strands, and if you must, make sure to follow up with reparative treatments.
Off balanced protein/moisture:
In order to have healthy curls, your hair must have a good balance of protein and moisture. Too much or too little of either can throw things off and make it difficult to maintain their health. Your curl's protein can be negatively impacted by chemical treatments (see a pattern here?) or overuse of heat. Make sure you're using a protein treatment on your curls after every single chemical service or every 4=6 weeks. You don't want to overuse protein treatments, as that can cause fatigue in your hair which leads to further damage.