no you don’t

@@murdered10thgen Yes you do, or at least you should if you care at all about your car enough to spend a couple minutes doing it, and you aren't replacing it with the exact same battery. It doesn't have much to do with the age of the battery like some suggest, but the type of technology and capacity the new battery is using. There are two types of batteries used on VAG (Audi) cars: (EFB) Enhanced Flooded batteries are essentially standard batteries manufactured to much higher standards. They have twice the endurance of standard liquid filled cheaper batteries and are fitted to vehicles with Stop/Start. (AGM) Absorbent Glass Mat batteries have three times the endurance of standard batteries and are fitted to higher specification cars with higher electrical loads. In these batteries the liquid is absorbed by a framework of glass mats. You can use an AGM battery instead of an EFB one, but at much higher cost. These modern batteries require different charging cycles from standard batteries. It's why when charging a battery with any decent newer external charger, it will give you charging options and settings to choose from. The vehicles battery management system will do the same thing. It's not like the old days when just any 12v off the wall charger would work on any battery. This is the reason why the car's battery management system needs to know what kind of battery you have. If you change a battery for one with an identical specification but from a different manufacturer, you may not see any error codes and it may charge correctly. If you change to a different battery without recoding, it may not charge correctly, even if you don't see fault codes, and that may affect battery life. A cheap OBD tool is a good investment if you have a VAG car, not just for battery replacements.

Yes. Unless it's the exact same battery you are replacing it with.