Worn wood paint effect - Tutorial

The material is a mask technique using a single channel of the texture, vertex paint and gradients.

First, make a simple wood material using principled BSDF
it's the base layer.

Paint material.
it's a second layer.

Separate the Z axis and use Math node to adjust the gradient. Z gradient is good to assets on the ground, in general the paint wears near the floor.

In this case i use dirty vertex color and invert him to make a nice cavity, to work in eevee, but in cycles have a pointness atribute.

Separate a channel from the wood texture, this is most important thing.
the output of separate node is a black and white image, is good to archive the cavity and details of wood.

Mix all masks. vertex colors with gradient and texture. put a color ramp to adjust the final mask and use the output to mix the two layers of materials.