I’d say about 20 years. I think after that, they get outdated. I was just talking with the director of the Woodland Park Zoo the other day, and he was talking about the Jones & Jones 1976 master plan, which was developed by the Hancocks, John Coe, Jones & Jones. And he felt it was really out of date. Although I still use it as a kind of a benchmark for talking about master plans. But I mean, his, his point was that, it was all about bio climatic zones, regional zones. And interpreting the interpretation for those zones was talking about the ecology of the area and the species and talking about species. And he said the modern, he felt the modern context really has to be changed.
