I think this is only true if you're building outside your GOPATH. In my case, build -v, build -v -i, and install all have very similar compile times and only show an edited file being compiled when executed from inside my GOPATH.

Each of those averaged 3.5s in my codebase, for example, on a freshly changed file. go install's second run is 250ms, but I assume that's because it knows the file hasn't changed.

go build -a shows roughly 60 packages and takes 16s, so I would notice if build or install were accidentally recompiling all of them.