1-2 weeks
i normally rotate a deck out within one to two weeks when they start to clump or just feel sticky into the used card drawer they go.
especially at the rate ive been practacing latly and thats 2 to three decks that last 1-2 weeks while i am practacing i have 2-3 decks on standby to rotate in and out depending on if the deck starts to feel hot or its getting sticky and needs to rest.
thats at on an 6 - 8 hours of practacing everyday if not more, there is constanly a deck of cards in my hands.