Optimized Shaders + Mesh + Textures what is the best approach?

So I had to optimize a big scene recently and it made me start wondering about my workflow... in terms of materials/unwrapping and texturing.

1)Materials
3)textures
4)The amount of materials on one object
5)same material & textures on different objects

Oke so I tried lot of different techniques and i'm not quite sure what the best one is. For example I made a scene with repeating materials so I had a material for metal,glass,ground ect.. all repeating nothing unique...
and I was using this for all objects in the scene which used that material. Now is this a good way to build your whole game? I'm not sure if that a optimized way to handle things because I had a huge mesh using 8materials and a few smaller ones using a bit less but from the same pool of repeating textures + materials.


Now another approach that exists of course is that you use 1texture and 1material for each object specifically. Is this better?

I don't know what to do anymore when creating assets to be fair. Is there like some guidelines I can follow do X for big meshes and Y for smaller ones or approach z for everything or can I just use a material library for each material in the world cloth,leather,stone,glass ect.. and then only have a few unique textures for specifc things?

I just want the most optimized workflow possible.

Thanks in advance.