Sleep training is not a matter of just letting your baby cry itself to sleep. It means looking at the whole picture to eliminate the reasons why a child is not sleeping through the night or taking good daytime naps. This may be due to many reasons i.e. bad habits, colic, reflux, illness, lifestyle, arrival of a new baby, holiday to name the most common reasons. Babies from 4 months to an older child can be sleep trained and most problems can be resolved within 48 hours.
Parents often don't have the confidence to do something about it themselves because they feel too emotionally attached and lack confidence.