Sibling comment says "diversify", and I tend to agree. I've seen some shit, man. 2000 dot bomb, 2008, bumps along the way. 2000, I was in tech stocks like everyone else, lost a bunch. 2008, learned my lesson and was much more diversified. Lost some money, but not nearly as much as others. It was amazing watching, say, the S&P crater while our portfolio..just didn't. It just went down a fair chunk, and came back later (and probably didn't come back as much as it did for those that held on to their equities).

Diversification is a smoothing function. You won't get as much upside holding 25-30% bonds, but your portfolio won't suffer as much on the downside. If you're young and not ready for boring old-people investments like bonds, at least limit your tech stock exposure. Go buy boring utilities or something, maybe Berkshire Hathaway B shares.

One other advantage to diversification that I hear very little about is this: if you have to sell in a down market, you can sell your bonds and hold on to your equities in the hopes they'll bounce back. Regardless, you're not held to selling depreciated assets like equities, you can sell the bonds which are boring, but probably actually went up while everything else turns to shit.