If my render takes more than 1/2 an hour, I disassemble and render in pieces and reassemble it in a graphic program.  I've had too many cases where I've let my computer run a render for hours and hours, only to find that it had actually frozen up or something.  So now I just hide stuff and render in sections.

"It is good to see ourselves as others see us. Try as we may, we are never
able to know ourselves fully as we are, especially the evil side of us.
This we can do only if we are not angry with our critics but will take in good
heart whatever they might have to say." - Ghandi