Just wanted to do some simple modelling lesson and texturing.
The bump for the sofa was mathematically calculated by following the CG Masters Chair material. Now I think I can employ those basic texture for leather items. It was great fun.
My car keys are much dirtier! Especially in the grooves of the metal. It is also worn on the plastic so it is shinier where my thumb twists it to the right,
It looks good in my beginner eyes, far better than anything I could produce. Maybe the ring is a little small.
And the roughness a little high on both the ring and the blade of the key.
Do you use an enviromental texture for the metal to have something to reflect?
Thanks for the critique 
This is relatively a new key with just mild scratches and dirt. That’s why the remote is so clean.
Thanks for the critique
The ring is of appropriate size, but the camera perspective makes it look small.
About the roughness, I am getting mixed critique. Some it is too shiny, others say it is not enough shiny. So I will leave the image there as for now. I looked closely at the car keys and found them to be not much reflective
Yes, I used an HDRI for the lighting and a spot lamp. The blue light is actually coming from the television 
Maybe it is time for me to buy a new car with less worn keys!
Keys generally have teeth, not just pointy areas to push the pins into place. I might also suggest vertical lines along the edges to show how the key was cut + the scratches that occur from inserting it into a lock