The disadvantages of traditional bonded hair extensions:
The application of bonded human hair extensions can damage your hair.
Expensive! The bonded hair extensions only last 4-6 months, and then you need to reapply them.
Inferior quality hair will matte and tangle after a few washes. It may be hard to tell the quality of the hair just by inspection, as hair that has been stripped of its cuticle will have a silicone layer to make it appear smooth and shiny. Silicone can wash out in a few washes exposing the damaged hair.
They may fall out - due to the extra weight, or damaged and weak natural hair (the reason why women want extensions in the first place!)
With traditional bonded hair extensions, you need to avoid coloring, tinting, perming or any other chemical processes as it will weaken the hair