I do this as well, mostly because I do a lot of third world traveling and it's easy to get your card cloned. I only keep $500 in the checking account linked to my debit card, and the rest in a savings account that I can transfer money from instantly. I did have my card cloned once and this technique saved many thousands of dollars from being spent. I would have recovered it all eventually but it takes weeks and it would be a disaster while on the road.