My lo is just 9 months and you can count on one hand the number of nights she's slept through, I have to say its worked well for me, as a good night is a bonus and I havent got too used to it and then struggle when they have a bad night as some people I know have!
As others have said they are so so different, I believe the advice is to only really start sleep training from 4 months, so I guess the expectation is around then??
Good luck