There is a lot of debate about this,  but what I have found is that it is not amount of time spent with your child that makes the difference,  it is quality time.  Finding a balance between everything a parent has to do and spending time with your kids,  is challenging.  As the mother of four children,  two being special needs,  and two under the age of two, I have found that spending fifteen minutes a day with each child by themself is very beneficial.  Some ways to do this are reading a book,  playing a quick card game,  and so on.  This way each child feels they are getting quality, one-on-one time with you.