It is very common for babies to wake up after only 30-45 minutes of napping.  This is because of the brain's natural change in sleep cycles, but it is not enough.  Babies need at least one hour of sleep in order to fully complete the sleep cycle.

Babies this age generally eat every 2-3 hours.  You should still be waking your baby that often to feed him.  Once he regains his birth weight, he can start sleeping longer periods at night.  The first few days your baby will seem to sleep all the time.  Let him sleep whenever and wherever he wants.  It is alright to let him sleep in his carseat.  At around 6 weeks, it is a good idea to move him to his crib.

At around 6 weeks old, your baby should be starting to sleep more at night and be able to stay awake for longer periods during the day.  Babies this age will begin to go to sleep between 9:00 and 10:00 at night and sleep for 4-5 hours before waking for a feeding then go back to sleep for another 3-4 hours.  As soon as your baby is sleeping in his crib, you need to establish a bedtime routine.  This will help him learn that it is time for bed.  During the day your baby should be taking 3-4 naps, two about 1-2 hours followed by 1 or 2 shorter ones.

By 3 or 4 months your baby should go to bed around 8:00 and only wake up for a quick snack, then go right back to bed for 3  hours or more.  The first nap will occur an hour to an hour and a half after waking and he should sleep at least 2 hours.  The second nap should occur  no more than 2 hours of being awake and last the same duration.  Most babies this age will take a late afternoon or early evening nap around 5:00 but only sleep for 30-45 minutes.  The 4th nap is dropped by 3 months. Nighttime sleep training can begin during this time, usually between 4 and 6 months depending on your baby.

Nap training can begin at 6 months.  Your baby should be sleeping 11 hours at night.  Some babies do not wake up at night to eat at this age, while others wait until closer to 9 months to give that up.  Naps usually occur at around 10:00 and 2:00 and last for about an hour or 2.  Some babies will still take a late afternoon nap.  It is more important to notice how long your baby has been awake rather than what time the clock says.  Typically, babies can still only be awake for about 2-3 hours before they are ready for another nap.

By 9 months the 3rd nap has disappeared.  Bedtime should be between 6:00 and 8:00 with no night wakenings.  Your baby should be sleeping around 11 hours and night with 2 naps during the day each about one to two hours.

Some babies at 12 months will already have moved to taking only one nap, but for most babies this transition can take up to six months. 

Most toddlers will go to bed between 7:00 and 9:00 at night and wake up between 6:30 and 8:00.  Their one nap is usually after lunch and can range anywhere from one to three hours.  Most children continue this trend until about the age of 5 when they no longer need that afternoon nap.