@mrbreeziewrites ,you just breezes cool air into my system. I got nocked off from my confusion of all the Engineering terms when i got to this point;

Imagine what it would be like if there wasn't anything like interchangeability and just the bearing of a car spoils and you have to buy a new car?

Imagine losing your computer just because you mistakenly break the screen or phone just because some key isn't pressing?
How would it feel? The cost? The files? Mehn, I can't think it!

At that point I came alive.So interchangeability is like when you steal chicken in your mama pot and replace it with beef.....Did I just typed that ?.....Well, nevermind.
I enjoyed reading this post. I learnt alot even including types of production systems.