Is it important to stick to a sleep schedule?

Yes. Absolutely. We all know the answer to that one anyway. We need a rhythm in our life. We need a schedule to tell our bodies when to wake, eat, poop and sleep. When we have schedule, we always know what's coming and what to get ready for. Start your babies early with their sleep routines, and they will make a lot easier for you to put them to bed at night.
Yes. The most important thing is to have a bedtime routine (starting at 6-8wks). Being consistent about this routine helps your baby learn that its time for bed and will increase the chance they will sleep better at night. Babies, just like adults like patterns and knowing what to expect. However when your baby is sick, you are traveling, have visitors be prepared to change your routines!