Here in Europe we prefer to use more foundation and replace old combs because of sanitary reasons. It is generally known that old dark combs may become a source of nosema, chalk brood, AFB, EFB. Yes, bees do prefer darker combs for wintering and storing honey. But if too much generations develop in the same cells combs are not dark, but black and heavy, cells certainly are narrower and SHORTER since every generation leaves exuvia and feces in them. Bees actually are smaller in comparison to those emerged in lighter combs and the other disadvantage may be that such combs take in less honey. So reasonable compromise may be the best way here, too - we should prefer brown combs. Best regards, Vladimir Ptacek, Czech Republic ([log in to unmask])