Gold A4

I think I'm ready to add a chip to my 2001.5 A4 1.8T, Q,Tip,ESP. I will probably get the APR with EMCS and 2 programs, stock and chipped. I am interested in the Throttle Body Adjustment/Fault Code Erase option also. Can someone who has this tell me how it works? Also, can anyone explain to me why these features are useful? How often does the TB need adjusting and why would I need to erase a fault code? I plan on keeping my stock ECU and swapping it for service and loaning it to people on this forum when they need it. My way of repaying people who have helped me here. I'm to much of a novice to give advice. Thanks all.