I once worked on a system where we were told to keep 18 months of debug logs (something that would have cost about $2k/month). When we pushed back and asked why, the answer was that occasionally (every month or every other month) there would be some customer issue that would need investigation that might result in a customer refund of $20-50 dollars.

Setting aside that the human time required for the investigation was probably close to $40-50, it was still not a slam dunk to get the business to shrink retention to a few days for critical debug.