I like running tests on a separate dedicated machine and enjoy a build environment that verifies each commit with a full test suite... but being able to run unit tests for a file on each save of a file is something that can save you some time pretty trivially.

I also disagree strongly about needing to run tests on the exact specs of your average consumer, most of us aren't writing software for a small set of hardware configurations so determining those average specs is likely not possible - but if you're working in an embedded platform or with specialized hardware I do agree that you absolutely do need to run tests on the actual hardware regularly, I'd still argue that those tests should be run on a dedicated machine and should be in addition to tests that verify the code is obeying its contract.