Select rendering

hey i am some what of a clumsy person sometimes when i am trying to meet a deadline and under a lot of presure
one of my big mistake is sometime i don’t apply a material to an object or i apply the wrong material to the wrong object
i was hooping to see some sort of post fix for vray sort like fry render swap
if not better
or having the option to only re-render the one object that need to be fix

also some new update to the vfb
on the vfb their could be a slider to controlled some preset rendering setting sort of like from test--------normal--------high quality
((sure not all computer are the same but these could be basic settings))
more option like the 3d max fb

I must admit I envy MentalRay for the wonderful “render Subset of Scene/Masking” lens shader which does exactly this: it has a built-in object list and only these (or only a mask) are rendered with perfect (no opacities) occluded portions where the other objects are.
It#s a huge time saver for rapidly changing jobs, not only for clumsy mistakes.