snagitseven

The fobs are identical until you memorize the settings for each key individually as 1 or 2 in the car - only one key at a time should be present when making the settings. Once you enter the car settings for each one, you'll have to keep track of which fob is which. I use a small red dot sticky on my wife's #2 key so we can avoid mixing them up.
I think you can change them at any time by re-memorizing them as 1 or 2 in the car.

Lookout57

I like on the 2017 Q7 key 1 has a smooth shiny back and key 2 has a textured back. Easy to tell which is which.

snagitseven

The two keyfobs from my 2016 A6 are identical - there is no difference in the textures.

Lookout57

On my 2014 A7 they are identical and shiny backs, my 2013 Q5 has identical textured backs.

Deanerh

So here's how I understand it works. In a sense the key fobs and the memory profiles stored using the buttons on the door are somewhat independent. So memory position 1 doesn't correspond to a specific fob. Whenever you lock the car, the seat and other settings are transferred to the key fob. So if you get the car set up like you want, you can store it using the buttons, but you don't have to (although that's probably preferable). I came from an Acura where the settings and the fobs are linked so the Audi approach is a little confusing.

I think the right way to approach this is for two drivers is to set up everything the way you want and save using the memory buttons. That way if you happen to grab a the other key, you can use the buttons on the door to get back to where you want. Problem I see with this (although I haven't tested to see if this actually happens) is if my wife grabs my key, then uses the door buttons to get her seats back in her preferred position, when she locks the car, her settings will get transferred to my fob. Also, not sure what happens when we're both in the car with my fob in my pocket and her fob in her purse. I know that today, we did that and the seat settings which had been in mine when we got in, stayed that way when we started the car. However, it looks like my settings got transferred to her fob. Kind of confusing and why it's good to make sure you have each person's preference stored in the car and don't rely on the fobs.

I uploaded a couple screen captures from the 2016 owners manual that cover this (somewhat).

Bobby K1

I bought a 2007 Audi A3 with only one key/pod. I had Norwell Audi, Norwell, Massachusetts order a new key/pod and went to the dealership to have it programmed. They advised me that an airbag recall was due and they completed that while I waited. Three plus hours later they informed me that the key could only be programmed to start the car and unlock the doors manually claiming that there was a problem with the car’s computer . I questioned why the existing key was able to be programmed to the car but the new one not and the response was that it had been previously programmed to the car.

They could dig deeper at a per hr cost. I decided that the partial key would suffice for a back-up. No local locksmith I contacted would touch an Audi key. Several years ago I did have a Honda key programmed at a local locksmith

Key $168
Program $135

Total=. $303

Audi , Norwell is an upscale ,well appointed and clean dealership. They did do Multi Point inspection and washed the car