I guess it depends on how you define 'sleep through'. It's different at different ages and for different parents depending on what they expect/want/need themselves. I think waking once a night at 7.5 months is pretty good, awesome actually, but it's all relative cause I only have my DS's history to compare it to and he was waking two to three times a night at that age and even a couple of weeks ago he was still waking a couple of times a night and instead of resettling quickly, it was taking 1-2 hours each wake up for him to go back down. We've also had weeks of 2 hourly waking etc etc. He got worse as he got older! In terms of sleeping through for more than 7 hours though, he did it a few times when he was 1-2 months old, then twice when he was 8 months old and then just this last week gone (14 months old) he's slept through about 3 times. We are still up some nights, others he has trouble going to sleep, this morning he was up at 5:30am so he's not consistent yet and this could be another 'phase'. I've had my hopes dashed too many times before to get them up too high again now

It's hard cause you want to know when the sleeping through will happen but it's impossible to predict. They're all so different. I feel/felt like I was running a marathon except I didn't/don't know how long I'd have to keep going. There's no way to pace yourself through sleep deprivation anyway. It just sucks.