When new born baby cries at night does your preschooler get disturbed in sleep? Does he wake up? I m planning to share same room for new born and my 3 year old. How convenient is that? What are draw backs?

Depends on how good a sleeper your preschooler is. My friend's 3 year old is such a sound and deep sleeper, it doesn't bother him at all when his parents mobile phone rings or beeps. That being said, some kids can be really light sleepers. I suggest you give the arrangement a trial run over a weekend and see how your older child reacts when baby cries. If it's difficult to get both of them back to sleep, best to let your older child sleep in his own room since he has to get to school the next day.