Sleep Training

If by "sleep training," you mean letting your baby cry it out at night so they get accustomed to sleeping longer hours without food and/or attention, that should wait until 4-6 months. But you can start encouraging good sleep habits now by putting your baby on a flexible feeding routine, establishing a bedtime routine, rocking them back to sleep if they wake up before it's time to eat, keeping the house dark and non-stimulating and not talking to them during nighttime feedings/diaper changes, etc. I'd really recommend reading Secrets of the Baby Whisperer, Babywise, and The No-Cry Sleep Solution. Babywise has been especially helpful in getting my now-5-month-old into a good sleep routine.

Thank you for your input! I will have to look into those books. I feel like we have a pretty regular schedule, but it's not strict by any means. He eats, naps and wakes up around the same time everyday and I try to encourage it.

Sounds like you're doing just fine, then! I wish I'd known about the importance of routines with my first. I'd made the mistake of reading a bunch of Dr. Sears' stuff about parenting babies and ended up nursing him all the time, trying to co-sleep, and generally making our lives a little chaotic. Learning about baby routines changed my life. Haha!

In my opinion, sleep training should start around 4-6 months. Before that, they can't self-soothe. An infant will usually only cry to have their needs met and will sleep when they need to sleep. Training is pretty hard to do because you can't train them to not have needs if that makes sense. After six months, most infants can self soothe at some level and are developmentally better equipped for sleep training.