Upon naming an item, it no longer grows in base value after being repaired on an anvil.

Normally, repairing items with an anvil would increase the base cost by two exp levels. However, by renaming an item, that item no longer goes up in price from being repaired. Effectively, this allows enchanted items to be repaired any number of times for the same repair cost; and since the cost maximum is never breached, it is possible to continuously repair and maintain the same enchanted items for indeterminate amounts of time (presumably forever).

Note that this was tested with multiple items, repairs with both raw materials and with other tools, on unenchanted and enchanted items, and in creative and survival mode.