Are your hair extensions destroyed from your over use of straightening, curling, or dying? I know mine are. I have something that will help your situation :) This process will help with synthetic as well. Most people like i do before I learned about this tip is i liked to cut the ends every once in awhile or just throw them away if they got too bad. But that will just make them short. And washing them all the time with shampoo/conditioner will just ruin them.
Things you will need: Fabric softener (any of your choice, personally I love snuggle), warm water (just fill your bathtub with water or use a big bowl. your choice), and your extensions/wig(s).
Step1. Fill your tub with warm water
Step2. Take your choice of fabric softener and pour as much needed in your tub of warm water and mix it.
Step3. take your hair extensions/wig(s) , but make sure you brush them with a wig brush or a pick to get any tangles out
Step4. put them in your mixture and leave them in for about 2-5 hours, then once they have been left in rinse them with warm water and let air dry , and brush them often.