I have a pair of speakers with the Aurum Cantus G2 ribbon tweeters. I have played them for 5 years and never have been shy with volume levels. I have no reason to believe they wouldn't last a long time.
They are, however, vulnerable to certain external environmental conditions, namely air and wind. The ribbon material is so thin and lightweight that they could be stretched out and damaged from
1. Anyone (or a young child?) blowing into them.
2. The faceplate being dusted with a vacuum cleaner.
3. Placed temporarily outside on a patio (for room painting, installing carpeting, etc.) where a strong winds could possibly deform them.
Other than that they are physically protected with a screen, and with a proper crossover network should not be seeing damaging frequencies below their range.
Steve