There is no "finish" with an unbiased renderer, you can render a scene for an infinity amount of time. Get some information about the difference of biased and unbiased rendering first.
To your scene, you complain that it doesn't look real, but this doesn't have something to do with the rendering time. The problem are your materials. Creating realistic materials in luxrender need some more knowledge about some fundamentals and the behaviour of these materials. You are not able to produce realism with the default settings. Another thing is that you have a difficult scene there. Creating realistic materials for organic stuff (like your dino...) is quite DIFFICULT at the moment, because luxrender doesn't support subsurface scattering yet. So I would recommend you to try simple things first to get a feeling for luxrenders materials.
I think he was more complaining about the gigantic holes in his dragon.
If that's the Sub-Dragon from DAZ, the mesh is... weird. LUX may not be able to make sense of the big discontinuities that exist in it - DAZ Studio's SubD feature seems to interpolate mesh properly on this figure to span the gaps, but I've had no end of failures in Blender with it.
Roter Sand und weisse Tauben \ Laben sich an meinem Blut Am Ende gibt es doch ein Ende \ Bin ich doch zu etwas gut