This is a great rule of thumb which helps build a kind of intuition around performance I always try to have my engineers contextualizing. The "lazy and good" way (which has worked I'd say at least 9/10 times in my career when I run into these problems) is to find a way to reduce data cardinality ahead of intense computation. It's 100% for the reason you describe in your last sentence -- it doesn't just save on hardware resources, but it potentially precludes any timespace complexity bottlenecks from becoming your pain point.