well sometimes it is more than a year or even longer before I notice I have something twice. If it is something one has bought a long time ago then I am sure many would never notice they have bought it twice.
If you know someone with a PC you could throw the History Manager on a MemoryStick and download your history from their PC. It’s saved in CSV format which can be opened in different programs where you can do a search. Just copy the product name from the product page, and use this for searching. That’s how the search function inside the program works.