Do I need a new license if I move to Germany from the US?
Yes. You'll have 6 months to pass the test! Unless you are from one of the following states:- Alabama Arizona Arkansas Colorado Delaware Idaho Illinois Iowa Kansas Kentucky Louisiana Massachusetts Maryland Michigan New Mexico Ohio Oklahoma Pennsylvania South Carolina South Dakota Texas Utah Virginia West Virginia Washington State Wisconsin Wyoming Puerto Rico these states can get a German license without a test.
International license with USA license will be usable for tourist short time- 18 years old may be a minor problem. If in military, then some laws after war treaty will give you exceptions. Brother drove/road motorcycle with american license and language road test certificate when stationed in Germany. EU /International license testing will be good most countries Europe for basics- signs are common pattern displays with some language . learn what einbahnstrasse means. Verboten. Badenzimmer other good to know.
Yes. Your license will expire eventually.
Yes. It is a matter of knowing what all the signs say and mean. Driving there means signs are written in German(not English) so you are the fish out of water. Left turn only in German is???(you need to know what the signs mean) Parallel parking only in German is? Cars parked here will be towed at owners expense in German is? Truck route only in German is? Speed trap ahead in German is? Ignorance is not an excuse to get out from a ticket & fine & tow away...and interrogation. The signage is going to be different. Obviously there won't be "Kangaroo crossing ahead" or "Causeway ahead". WTF is that? It took a rain for me to understand what a Causeway was. They are not allowing the "unknowing" on their roads. Basically the same rules for any other country. Can you read and understand? Those basics. No U.S. state can get a German D.L. without being able to read German...as all U.S. states main language is English. Right? Go to the DMV there. I do not know what it is called in Deutch (German) They will tell you there and quite possibly in English...what the deal is. Them are the folks that KNOW ALL THE FORKING ANSWERS. Me, I am just using "common sense"
No but you may need to go to a German DMV to take a test showing that you can drive on the otherside of the road without complication.