I don't quite understand how people get into the situation where their work can't fit on their workstation. I've worked on huge projects at huge tech companies, and I could run everything on my workstation. I've worked at startups where the CI situation was passing 5% of the time and required 3 hours to run, that you can now run on your workstation in seconds. What you do is fix the stuff that doesn't fit.

The most insidious source of slowness I've encountered is tests that use test databases set to fsync = on. This severely limits parallelism and speed in a way that's difficult to diagnose; you have plenty of CPU and memory available, but the tests just aren't going very fast. (I don't remember how I stumbled upon this insight. I think I must have straced Postgres and been like "ohhhhhhhhh, of course".)

When you're developing and only need to touch 0.1% of the product and 0.001% of the code, that's a total and complete waste of time.