Is it true that if you want your model to look realistic and high detailed you have to make the model look older (with wrinkles lot of details etc.) and sss shading will take the away finally?

Short answer: yes! The real world is very complex, and for getting realistic results, one must try to get as close to the real thing.
Objects normally have all kind of small imperfections, dirt, scratches… And real materials have lots of different ways to reflect, refract and absorb light…
The main point, however, is to keep the notion of scale. SSS, for example, happens in most materials, but in a such small scale, that it won’t be noticeable in the render, much because the scattering radius is far smaller than the pixel size.