Days on Til'raine were 20 hours long, and the year had 225 days in it. They didn't divide their year into weeks or months. While Til'raine was destroyed long ago, Vel'kira used this calendar as well, as do the scattered El'dari around the multiverse who have not settled on any particular planet that has its own day and year cycles.
As beings with potential lifespans of thousands of years, the Til'dari took a long view of the universe. They divided their calendar into ages of ten thousand years, giving each of them a unique, fanciful name.