One of the worst things about setting off high-resolution renders is the thought that all of the processing time could be wasted if your software crashes halfway through.
David Venables‘ free Render_autosave script fixes that problem, triggering 3ds Max to save renders in progress at user-defined intervals. If a render crashes, you can simply resume from the last save.
You can find the script, and instructions on how to use it, on the blog of Venables’ collaborator Jamie Cardoso. The only thing it won’t help you with is the need to leave your machine on overnight while a render is in progress.