I've posted about this around here before but I really think some of it comes down to metabolism (as well as personality/temperament). We did no sleep training with either of our girls but DD1 still woke for night feeds till 2yrs 9months which I felt she needed. She is a tiny thing who just eats and eats and eats but stays tiny like her father so I believe she was waking up hungry. At 2yrs 9months she started sleeping through consistently so we moved her into her own bedroom (was in our room in her toddler bed before that and in our bed before that) where she kept it up. She was still breastfed to sleep till she self weaned at 3yrs 3months and now we just read her a book say goodnight/cuddle then walk out for her to fall asleep on her own (I think she would probably have been ready for this earlier but whilst we were still feeding I saw no need not to use it to settle her at night because it was our one on one time after DD2 arrived as well as being quick and peaceful for both of us). She is a brilliant sleeper now, she even gets up herself for water or the toilet without any need for help (although if she did call out we would be there asap of course), the only time she has ever woken me in the last few months is when she was sick with a terrible cough (she's 3yrs 6months old now so this was all quite recently still I guess).

DD2 is very different. She sleeps with us at the moment (conveniently arrived just as we moved DD1 into her own room so it worked out well for us) but only wakes for feeds occasionally. She is a well built little lady, she eats infrequently during the day. Last night she didn't wake at all for a feed, just once to move into a different position. The night before she woke twice, the night before once. She also has taken to solids a lot quicker than DD1 did, she eats fairly well and decent amounts whereas DD1 didn't even really begin to swallow solids till after 9months. DD2 is 8months.

Both were treated in exactly the same way; in our bed from birth, fed to sleep and on demand each wake up. Both have had all of their naps on my lap or in the sling/carrier too (think DD2 has had maybe two nap away from me in her 8months) so I've done all those "bad habit" techniques with both lol. I just think DD1 needed the night feeds whereas DD2 doesn't seem too (she is the size DD1 was at 18months at 8months so they are polar opposite builds).

I'm prepared to give another 3yrs with DD2, I think that to me is what seems reasonable but it looks like I won't have to wait nearly that long this time. DD2 will move into DD1's bedroom when she is sleeping through consistently, we are about to move her into a cot in our room now that she is doing so infrequently (she will begin in there and then be brought into bed with me as needed so will end up in our bed often). When she is only waking occasionally, the cot will be converted into a toddler bed and I will lay with her to nightfeed returning to my bed once she has resettled so we sort of just gradually change as they start to on their own. I'm not sure if that is training because we never really pushed or did anything (mostly out of pure convenience and laziness) but just moved to the next stage as it seemed appropriate, I don't feel like we did any training.