Fiqh-us-Sunnah Volume 5, Hajj and ‘Umrah, Fiqh 5.041A.

Saying talbiyah is desirable in the following places and times: when mounting one’ s mount (or any means of transportation), on arriving at a place, on going up a hill or down into a valley, on meeting another group of people, at the end of every prayer, and early in the morning. Ash-Shafi’i said: “We love to say it at all times.”