Jim Harbaugh made waves when he equated the first day of spring practice (and later fall camp, too) to the birth of a team. It's a refrain he's gone back to several times before and since he came to Michigan.
And spring football does have a strong sense of discovery and newness. Veteran players who did amazing things are now gone; young guys who haven't proven themselves try and fail. It's like learning to walk, or, in this case, learning to hit people in pads.
Anyway, you could say it's the perfect time to take stock of the biggest questions.