When Samy was 3 months old he would wake up sooo early... 5:30-6am and would scratch on the door and cry a little until we get him in the room or tell him to cut it out. At 4 months he started waking up a bit later, around 7-7:30am but he was completely in the dark and if we did not open the door he would rip the pee pads into pieces. Now he is 5 months old and would sometimes sleep until 12pm on weekends. This Easter season I actually had to wake him up as it was 1pm and he was still sleeping heheheheh and then took him into bed and he slept until 3pm while we were watching tv. With age they sleep more and more which is really nice on weekends and holidays
I know this because i take care of this 2 year old female yorkie and she sleeps a lot during the day and all through the night!
In the mornings now when we get up to go to work - around 8am - we have to wake him up!!!