"Why do I have to 'jiggle' my keys in order to get the lock to work?"

Your key does not work properly because you are using a poor copy or a copy that has been made from a copy.  Keys are much like copier copies: whenever you copy a copy of a copy, you get poorer and poorer results.  Similarly, no key machine copies perfectly. As a key moves farther away from the original, the less accurate it becomes.  It could also be that your key tumblers have been worn down. Solution:  Find the original factory key and make copies from it.  If you cannot find one, you may need to re-key the lock.  Always ask your locksmith for a "factory original" when he re-keys.  Also consider whether or not your locks are old and worn. Sometimes the key-way itself is worn out and the key has too much wiggle room and cannot seat itself properly in order to activate the tumblers.