Do classical guitars age and improve their sound like steel string guitars?

[Vognell]

Yes....and they tend to get a little stiff and unresponsive if left alone for too long... but not as bad as violins.

[offkey]

I don't know if they improve in sound but I am sure the neck angle changes quite often in classical guitars. Many older instruments have a higher action and more neck relief than when younger. Having spent a few years in the great internet guitar store trying first this then another guitar I will almost always prefer a newer instrument.