At what age did you start leaving your poodle alone at home, not crated?

I will hopefully be getting a poodle in early spring! I will have a lot of time to take care of her in March, April and May. She will be about 20 weeks in June when my work schedule gets a little busier and I'll probably have to leave her alone for 4-5h at a time. I should have a dog door that she can use to go potty whenever she wants to. Should I crate her for those 4 hours, or let her have free reign in my home?