We know that in general, Toyota and Honda products are reliable vehicles, but they do have issues with failures of ignition, door and trunk locks in Honda and ignition locks on Toyota vehicles. The failures are caused by the use of split wafers (tumblers) in these locks. As with any mechanical item, the weakest link will fail first and split wafers are a very weak component. Most wafer locks have a full wafer tumbler surrounding the key which is generally quite strong by design. While the failures are caused by different problems in the two manufacturers, the failure is always with the split wafers.
Toyota failures can be caused by worn keys, and cutting new keys by code every few years will lessen the failure. Having the key copied will not help! Duplicating only transfers the wear on to the new key. Make sure a locksmith or dealer originates the key on a computerized code key cutting machine from the key code, which will give you a key as good as the original key when the car was new. Toyota has apparently realized the problem as the newest locks do not contain split wafers.
Honda ignition, door and trunk lock failures occur due to wear on the split wafers. A very small protrusion on the split wafer makes contact with the side cuts on the key and this protrusion becomes worn down or off very easily, causing the wafer to slip past the stop point on the key when it is inserted. Also, a worn key will hasten a failure but these locks also need regular lubrication with a very good silicone or Teflon lube. Do not use a solvent-based lubricant (it dries out) or graphite - graphite can make a nasty black mess.
When these locks fail, they can be repaired by a professional automotive locksmith or a dealer that is willing to do the repair correctly. Automotive locksmiths have the skill and the service kits to service these locks properly and many dealerships and repair shops just cannot be bothered to do this. The dealers generally just replace the complete lock with a new one that operates with a different key. There is nothing wrong with a new lock, but there is nothing correct about using a different key for the ignition, and in most cases, this will cost many many dollars more than repairing the original lock. Even if it is determined that a new lock is required because of excessive wear in the lock itself, the new lock can and should be re-keyed to the original key code.
These cars were designed to operate with one key for all locks. The factory has the code for the original keys on file against the VIN# in case they are lost. Registered locksmiths with security clearances can access these codes. If the lock has been replaced by a dealer or another repair shop, the factory original key code is now no good, and therefore if a locksmith gets a call from a customer with a lost key situation, and then accesses the original key code from the VIN# and then cuts a key by the code, it will not work. This means a very expensive disassembly of the lock and hand-fitting of keys to the lock, on top of the charge for the code access and cutting that has already been done. When replacing the lock with a new one the solution is simple, have a professional locksmith rekey the new lock to match the existing keys. As most of these vehicles also have transponder keys, replacing the keys and reprogramming the new ones adds even more cost to the vehicle owner.