Interesting thing about the above two ideas is that the original version got only 7 votes over 3 years, yet the new version has had 83 votes in just 3 months.
That makes me think that duplicates are not always bad. Due to its age, that old post wasn't going to get any further support no matter how long it stayed, but the support for the newer idea proves that the idea has more merit than was thought at the time when it was posted
I agree there are certain subjects that probably should not be allowed in labs again. Anything proposing yet another permutation of goodybags is a minor tweak to a feature that already exists, not by any stretch of the imagination a new idea, and we really don't want more proposals of goodybag permutations. Likewise, if an idea already has popular support -- such as itemised billing, which continues to get further support despite its age -- it should not be reposted and supporters should continue adding their votes to the original idea.
But perhaps duplicates of old ideas that have merit but were not supported at the time should be treated differently?
Perhaps old ideas that are over a year old and have not reached the "looking into it" stage should be archived, so that the idea can be updated and proposed again without being considered as a duplicate -- but if the new version makes it to the "looking into it" stage, previous similar proposals can be linked to the new version, and if the idea ever gets implemeted, the original proposer gets partial credit for the original idea.