Binary stars of different ages?
Stellar encounters are very rare outside dense stellar environments. Such dense stellar environments are only found in a star's birth cluster, where all the stars are coeval to a close approximation.

Thus the switching and capture you refer to is probably common in the first few million years of a star's life, but would occur with stars of a similar age. Thereafter, once a stellar system is "in the field", encounters with other stars hardly occur at all, but are not impossible.

I am not aware of any binary where the components are thought to have a very different age.