How do you decide your investment risk when your career horizon is so uncertain?

One thing I've never really understood is when people say things like, "I'm 25, I've got another 40 years of work ahead of me, so I'm 100% in tech," or "I'm young, I can afford to take huge risks." How do you know you'll actually have 40 years of stable employment? You could burn out. Your industry could change dramatically. AI could replace parts of your job. Your income might fall. Or you might simply realize that corporate life isn't for you anymore and decide to pursue FIRE much earlier than expected. Working for one of the world's largest consulting firms, I'm already seeing AI eliminate roles and reduce hiring. Friends in tech, pharma, and other industries are seeing similar trends. That makes me question the common assumption that young investors automatically have decades of reliable employment ahead of them. So I'm curious: how do you actually determine your appropriate level of investment risk? Do you base it mainly on age? On your ability to earn? On your financial goals? On the possibility that your career may be much shorter or less predictable than you expect? I'd be interested to hear how others think about this, especially those who balance long-term investing with the possibility that work itself may become less certain over the next couple of decades.