Khloe (older DD) co-slept with us up until the day I went in to deliver and we had the hardest time getting her to sleep alone at anytime. Before her sister was born she was a dream to get to sleep whether at night or for a nap. She was 100% happy on her own playing. Since Keira was born she fights us to nap despite tell tale signs she is tired, and fights us even more to go bed specially now that she is in a toddler bed and knows she can easily get out and get into stuff. I often find now that I need to tell her to come cuddle with me when she is acting tired and she will usually fall a sleep if let her rest her head on me and rub it. Keira naps whenever she feels like it, but she too will fight it and I usually end up having to nurse her and when she is almost asleep and removes her latch I have to rock her and hold her for a good 10-15 minutes before I can put her down. As for night sleeping with her I really think it depends on her mood, some nights she will take a bottle in her pack and play and pass out no problem on her own, other times she has to be in the bed snuggled up to myself or DH. I think the best option is if you know their tired signs to find something that works for both of you whether it is rocking them for some time, rubbing their head, nursing/bottle or just snuggling up.