Don't Install If You're Traveling
If you're preparing to travel or currently on a trip, you might want to hold off on the installation until you're back home.
We've spoken to many travelers who wind up with a broken phone or a busted app/service because they decided to install a new operating system on-the-go.
If you're on an important business trip or traveling in a new city/country, having a functioning phone is pretty important.
If you're relying on your phone, you hold off on the Android Pie upgrade until you're back at home. There's no reason to jeopardize a fun trip with friends or an important business trip.