In our models we try to minimize usage of textures and make all details with geometry where possible (e.g. reflectors structure, tire thread, emblems, grills etc).
This approach optimizes number of materials used in scene and simplifies materials setup (for example: instead of a couple of chrome materials with different textures we use only one chrome material). Absence of textures also allows to convert to different formats, so after conversion you don't have to relink textures.
In some cases, however, we use textures for materials with patterns, which can not be made with geometry, such as carbon, leather, wood etc. Complex car liveries (with decals, signs and different stickers) are usually made by textures too.