We have blogged about this before, but it's worth repeating since debit cards are so wildly popular.

Readers Digest recently covered some of the traps you can fall into with these. Pay close attention to the part about hotels, airlines, gas stations and rental car companies putting holds on your cards. Remember, they only keep this money temporarily, but during that time, it's gone from your bank account. For background on how these holds work, see our recent blog post.