The senior-to-staff jump isn't about being able to solve harder problems. It's about being able to spot which problems are worth solving at all — and which ones you should explicitly decide to leave alone for now.
Most senior engineers I respect can debug almost anything. The staff engineers I respect debug less, because they've designed systems where fewer things break in the first place — and when they do, the failure modes are obvious.
Three things staff judgment looks like in practice
One: choosing which problems are worth a meeting. Most aren't. Most can be resolved by writing the answer down once where the right people will find it later. Defaulting to async is judgment.
Two: pushing back on shiny tech. The technology that gets a feature to launch is rarely the technology that should run it for three years. Boring stacks compound; novel stacks expire. Picking boring on purpose is judgment.
Three: explicit non-goals. Saying 'this thing we're shipping won't handle X, and that's fine' is more useful than any architecture diagram. Most outage retrospectives I've read trace back to an implicit non-goal someone had — they just never said it out loud.
Senior engineers solve hard problems. Staff engineers prevent them.
What it isn't
Staff judgment isn't being right more often. It's being honestly uncertain in public — saying 'I'm not sure, here are the two options, here's the one I'd pick and why, but I could be wrong' — in a way that helps the team move without forcing them to either disagree or comply.
The work is mostly invisible. Nobody points at the migration that didn't happen, the meeting that became a doc, the service that didn't get split. But over a year, the absence of pain is the signal that someone made a lot of small good calls.