Normally, frogs are made of ebony with silver mountings. Frogs of ivory or tortoiseshell with gold mountings will double the price of a bow, since bowmakers save their finest wood for these bows. Fancy inlays and jewels do not add anything except their own value to a bow, although they may appeal to collectors. Aside from the fact that fine bows improve with age and use, antique bows will be many times more expensive than modern bows. This increased price does not necessarily indicate a correspondingly better performance in playing but instead indicates value as a work of art.
Bows do improve and mellow with age and use, and the sound they produce improves considerable.
But a bow with a great sound will develop to its full potential rather quickly if played regularly, probably within ten years or less. Tourte, Peccatte, Voirin are the makers who represent the pinnacle of bowmaking, and are the models by which all bows are judged. They are also the most expensive, being much sought after by musicians. All other things being equal, a French bow will always cost more than an equivalent German or English bow, so if you are looking for the most playing value for the money, do not buy a French bow. A fine German or English bow of the same quality will cost less.