I replaced the originals because of the yellowing. I'm sure the originals last longer. Don't want to another mistake, already have the dreaded under hood conical filter that I'll never live down.Then you probably have reproductions, not real ford lights.
I drove my car daily for 10 years, never was it in the garage (it is now) and I've only done the headlights twice ever over a total of 20 years.