How long does it take to sync passes in my wallet with my Apple Watch?

How long does it take to sync passes in my iPhone wallet with my Apple Watch wallet? I just got a new Apple Watch and I want all my passes on my watch. The passes that were on my old Apple Watch and are still on my iPhone didn't show up on my Apple Watch, what do I need to do?

All I can find out is an entry in the "Apple Watch User Guide" that says "Passes in Wallet on your iPhone automatically sync to your Apple Watch."

When does this happen, how long does it take, hours, days, never? Is there a way to speed up the process?