I simply close my eyes and imagine the battle hardened survivors aiding in the training of their new brothers in arms, thereby giving them more experience than normal first time units

ps: I had a Teutonic Knights unit experience-lvl 8 reduced to one (1!!) knight. Had him retrained and filled with Teutonic brethren before sending him on a crusade with the Emperor`s brother Jan von Salza (later known as Jan the Crusader). Later Jan von Salza got a Teutonic Knight retainer and, to me atleast, this retainer was the same knight who rode alone into Nuremburg and personally trained a new band of knights.

He stayed with Jan von Salza until his untimely death by assasination in Sofia years later.

I loved Jan von Salza....*sigh*