As an engineer who's been on the front lines of circuit board testing for years, the worst thing is dealing with repeated plugging and unplugging, and the resulting poor contact. i once had a critical bga chip test fail because the probe contact was unstable, which caused the entire batch of products to be delayed – a real headache. but now, the advent of dual-tip probes has completely changed that. they're made with high-purity phosphor bronze material and..