A common call we get is about Honda ignitions and door locks not working. Usually the key will be working fine one day, be a bit finicky 2 or 3 times, and then all of a sudden just stop turning in the ignition or door. The cause of this is the split wafers in the door lock or ignition itself. They wear much faster than the full sized wafers. Eventually, one or more of the split wafers sticks so far out of the plug that the key will no longer turn.
The solution to this is to remove the lock and replace the split wafers. Quite frequently the key needs to replaced as well. Usually we simply re-shell the keys and cut the new blade to match and reuse the old electronics and transponder.
The cost to replace the split wafers in an ignition or door and re-shell and re-cut the keys is around $500 and it can be done on site (weather dependent). This is about half the cost of having the dealer replace the ignition with a new one (in which situation you will have to carry two keys) and you don’t have to bother with getting the car towed.
Check this site out for a good view of the wafers and plug.
I hope this was helpful!