I think it is important to be home for a while when you first get a new puppy. You have to think that they are leaving their mom and litter mates and coming into a new home and if you are not there they are coming into an empty house. At least if you have a few weeks off you can help the puppy get adjusted and do some special bonding to help the transition easier for the new little one.
I am home most of the day and my dogs hate it when I leave but they do get over it!! lol I think I just feel guilty when I have to go out.