But how far? Corrections of 30% in say Bitcoin are common. Does this matter? I would say not -- it's not something I lose sleep over. It's fine, boom and bust.

If you buy in, buy in during a consolidation phase, when you see the price is stable. Ethereum had a huge run up, yet then consolidated for around 6+ months around $300. I would say that is healthy. Now it's heading higher. "Fundamentals" aside, of course.