Hi L., My daughter wakes up throughout the night as well, she's 7 months. It's normal.
I'd like to encourage you to consider other alternatives to CIO. My daughter easily goes back to sleep if I nurse her and rock her. I lift her out of the crib, and snuggle with her in the rocking chair. It only takes 5-15 minutes. If you are not nursing, you could keep a full bottle ready and anticipate her waking up next, room temp should be fine, even water at room temp may work.
Even when getting back to sleep takes longer, I just remember that they are only small once, and holding them is not going to last forever. I believe children need to have their needs met day and night. Why listen to them cry when it breaks your heart, and theirs. Cuddle, read to them, nurse, rock. They are babies, that's what they need!
Our family has chosen to co-sleep, it has been a wonderful bonding experience! And I get so much more sleep and daddy thinks its so cute! My little one comes to bed with us when she wakes up in her crib around 11pm. More and more parents are choosing to co-sleep due to working parents, nursing children, and fragmented sleep. It has been proven to help their emotional and inner-personal connections as they grow too.