I favour a simple set of guidelines where questions are tagged by geography as follows:
- tag a country if the question and answer could be applied to anywhere in that country
- tag a county/state/province if the question pertains specifically to that county/state/province
What this means practically is that the vast majority of questions should only have one geography tag. A question should not be tagged with the county/state/province only because it mentions that county/state/province. A question about a very specific locality (e.g. county) should not be tagged with the country as well.
If you are thinking about adding multiple county/state/province tags to one question, then a country tag is probably more appropriate.
Many questions will be about ancestors who lived in more than one country, but this does not mean that every country or place mentioned in the question must be tagged. Choose the one, or possibly two, places that are pertinent to the question and tag accordingly. For example, a question about the death of an ancestor from Albania who immigrated to the USA does not need to be tagged albania because that has nothing to do with finding the death record.
The nature of country/state/province tags will vary by country, and the scope of such tags needs to be determined on a country-by-country basis.
Avoid tags with overlapping geographies where possible. I know this is easier said than done, but again I think has to be determined on a country-by-country basis to keep our set of tags manageable and useful.