Well, you see, Shahrisabz is not as rich in historical landmarks as Samarkand. You can easily spend half a day there, but not the the whole day, that's unlikely. There isn’t much to see unless you’re particularly interested in history and the era of Timur and everything associated with it. Still, half a day is more than enough.

In my personal opinion, the journey from Samarkand to Shahrisabz is actually more interesting than the city itself. The road goes through the mountains via the Kitab Pass (by the way, they prepare the most delicious tandir (meat) in Uzbekistan there). Along the way, you can also see the Plateau of Demons and the cave of the biblical David.

And if you go now, you might catch the blooming mountain poppies at the Kitab Pass.