The ADB looks exactly like a passport (identical format). Your license(s) appear in one section, your PPC's etc. appear, and your medical validity (stamps or stickers) appear later in the booklet. It has pages after you license(s) where an authorized person can endorse the booklet to give you a type or class endorsement on the spot.
I've never been eager about it, 'cause it's really bulky compared to the old paper license, but it is an all in one document (the medical used to be a separate piece of paper), and it is absolute photo ID, which the old paper one was certainly not.
The ADB itself now has a ten year validity, which is primarily based upon the age of the photo in it. So, your license never expires, but the booklet can. I had let mine expire (confusion about a seven year validity - now understood). Transport Canada would offer me a temporary license if the ADB took too long to arrive to me.
Not my first choice for a system, but it works...