Until 2019, I preferred finding the business strikes in my change. They mingle with proofs just fine, regardless of condition. For the most part, anything starting from 1980 (when I started filling holes) were pulled in "uncirculated" condition anyway.
If I could not find in change, I would buy them at a coin shop or show. Sometimes that meant buying an uncirculated mint set I had to bust, usually for the NCLT stuff, for example: SMS sets, 1973 for the Ikes, 1987 for the Kennedy
halves, etc.
Then 9/11 happened. My access to Denver coins was limited as travel conditions changed. I had family in California to help, but the Denver coins tended to not be as "fresh" as they used to be. Sometimes I would seek better example at the shows.
2009 was an odd year. I found everything in change or from family, but I also bought an uncirculated set to get those 95% copper cents.

Starting in 2019—prompted by the West Point bonus coins—I started filling my albums from US Mint purchased uncirculated sets. COVID sealed the deal, I was no longer hunting change.