I check when my passport expires 
 What will happen to us when Google crushes? I also do all my reasearch on Google. 
I also check when is their tourist season - don't want to have too many people in my shots. 
Any nice events: like carnavals, religious parades. 
Cost of food per person per day, for us its quite an expense - and in Germany we could eat much cheaper than in France. 
Before leaving for the country I run Google news for a while - don't want to end up in the middle of a political event or a metro strike, like London on New Years eve in 2005.
And shooting permissions: like in Europe we were told not to point cameras at kids, in Turkey we read we had to get special persmissions to shoot in certain places, and in Muslim-African countries you need to ask the person if you can shoot them as part of a background shot. 
In South AFrica you just don't take out your camera when you are alone