When we started working on BTC Map, we inherited about 8,000 places last verified before 2015. It quickly became clear that adding new merchants wasn’t enough, we also needed to make sure the existing data was still reliable.
Unfortunately, OpenStreetMap doesn’t make it easy to figure out if the data is still fresh. There are a few optional tags that can be used to keep track of the timestamps, such as check_date and survey:date, but most Bitcoin merchants didn’t have those tags, so I had to figure out the dates of the most recent full verifications and add them manually.
It took me a few weeks, but now we have full timestamp coverage, which allows us to measure the age of our data. It currently stands at ~460 days, and I hope we’ll be able to bring it down to 365 days or even lower.