Thinking of trying the CIO method of getting baby to sleep. Any parents can share their experience?

Baby will feel insecure if leave for crying alone. I will never try CIO when baby is young. But when baby is older and able to understand what I am saying, I will just tell him/her it's time to sleep and you should sleep in your bed. Yes there will be some crying but that is the way the kid let out the emotions and after few cries they will stop. Thus, if you using CIO never leave baby alone but to stay beside him/her.