DS2 (21m) is an early riser. He has never been a great sleeper, but has been mostly sleeping through the night for about 4 months. He goes to bed at around 8pm, after a bedtime feed - sometimes he feeds to sleep, sometimes he will into the cot awake and settle himself. He naps quite well in the day time - 1.5 to 2 hours.
Until recently, he was waking at 6am, which I could deal with. However, in the past week or so it's been getting earlier. This morning it was 5 - DH tried to resettle him for about 20 minutes, but to no avail - when he wakes up, he tends to be wide awake and ready to go. He came into bed with us for milk like normal - fed for around an hour, and then fell asleep till about 8am - this is unusual, which makes me think that 5am is just too early for him.
He does seem to need less sleep than DS1 did (or does now), and it doesn't seem to affect him in the daytime - although sometimes he will need his nap much earlier (but then seems perfectly fine to go through to his normal bed time). I'm not sure whether we should try to train him to sleep longer, or just accept that he's an early riser, and go to bed earlier ourselves.