Sorry this is a long one.... Bit of a loaded question. Tried to be quick and to the point. Also asked on the 9-12 month board.
Quick background - baby is 10 months and has been a great sleeper up until this point. Overall I think she's at some sort of developmental leap and/or over tired.
The issue - The last week she has consistantly gone to bed at 8:00 pm which is part of her routine and normal, but wakes up at 10:00 pm crying. We did have a bad diaper rash the last week as well so I would take the opportunity to get a dry diaper on her. Diaper rash is healed, and other than waking up, she's fine and should have no issue sleeping at this point. We dabbled with CIO but my husband and I didn't go into it with a solid plan. However, what we saw was she would become more and more hysterical each time we would go in (3, 5 and 10 minute intervals) that she was shaking and couldn't settle.
The question - Once she has reached that point of hysterical crying, do we continue to go in and leave her crying as she was? Do we stay until she's settled down? If not - that would mean we are in there for atleast 30 minutes - easy.
Finally - we have a trip with a three hour flight next week. Should attempt CIO this week, only to have her schedule/environment disrupted next week or hold off?