Something that I thought about and seemed an easily answered question, but then began to think about it (maybe too much), but does a tuned car ever need to be re-tuned after a period of time without any add-ons since the original tune?

 

Nope, but it's good to check the tune every once in a while with a scan.

 

that's what fuel trims are for. unless your tune is open loop, then you get to play the human fuel trims and adjust it yourself

 

If there ever is a perceived need to retune for age, then it's essentially a band-aid for another problem. Routine maintenance and a good tune from the start will ensure a long-lasting, desired output. Factory cars don't go in for re-tunes. The do go in for plug changes, vacuum leaks, engine rebuilds, etc.