The objects they contain were collected by researchers who used the best methods available to them at the time and who recorded what they could document within the frameworks of understanding that existed when the work was done.

But the methods available for analyzing those objects — for dating them, for extracting biological information from them, for situating them within larger genetic and population-historical frameworks — have transformed almost beyond recognition since those collections were assembled.

This means that old collections frequently become scientifically more valuable as time passes, not less.

An object collected in 1949 and analyzed with 1949 methods might have yielded limited information.

The same object analyzed with 2016 or 2018 methods can yield information that was literally impossible to obtain when the object was first collected.