Traditionally, time off was calculated in vacation, sick, personal, and other categories regulated by the company. This policy has morphed into a Paid Time Off (PTO) structure.
I truly believe that taking time off when your children are born is extremely important to the well being of your child. Newborn children require a lot of love and care. Plus, the bond developed between parents and children is put into place in the first 3 years of a child's life.
The economy is still rough, so thinking about a career change is a scary thought. Here's a good hypothetical to think about...and maybe put your entire career path in perspective.