Looking at someone's render settings, trying to use them directly, without justifying those settings against the required similarity of YOUR scene to THEIR scene, makes very little sense. Consider this:

Here is a scene lit with 4 point lights and an "evening" sky dome outside. Almost all the light is coming from the point lights. This is 35 samples. This many samples is more than enough. This scene is a "hamburger" for which $35 is more than enough.

Now for the "BMW" scene. Note that the props and materials are identical, and on those terms you'd say the "Hamburger" is pretty much the same as the "BMW". But the light situation is completely different, and 35 samples does not work here AT ALL, same as $35 is not enough for a BMW.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)