Yes, just as Wardred says. You video card has limited amount of memory, if your Blender scene is too heave, when you hit render and it can’t all be stored on memory, then it’s time to save up on resources.
You can start by turning off subdiv to objects that are for away on your scene and don’t really need that much geometry. See if there’s objects that can get away with 1 level of subdiv and still look good. That will save you on vertex count. Next up try linking object data on objects that are alike. For example bolts on a machinery, you shouldn’t really be Shift + D and duplicating them when you can save up on resources and ALT + D to have linked duplicates. If they are already their own duplicate, you can Control + L and link their object data. Next up try getting your 4K textures to 2K, if you got any. Next up see if you can have your assets on a separate files and link them into one master file where you do the layout of everything. Linking your geometry saves up enormously on memory. And last but not least, you can render your scene by chunks and put it together in compositing. That is what used to be the old render layers. And then there’s always the dream of getting an awesome super expensive video card that will make your life easier until you start doing come complex scenes again and also make your expensive card run out of memory.
