Before I learned about Vanguard and index investing, I bought a couple shares of various stocks, with no real plan beyond 'I'M INVESTING LIKE AN ADULT' and 'BUY AND HOLD'. Now that I'm (theoretically) older and wiser, I'm thinking about what to do with them. I'm content to let most of them ride, as my income has increased a ton and taxes blah blah blah. However, I bought a few shares of a stock that had tanked, and it has since split, and recently spiked again, giving me R I D I C U L O U S returns (on paper). Even at it's current elevated state, it's still less than 3% of my total invested. At it's current elevated state, it's close to 3% of my total invested!
So my question is really around what criteria do people use to unload this sort of thing? Some sort of rebalancing criteria? Certain percentage return? Percentage of portfolio? Just dump it whenever? Wait till my income goes back down? Something else I'm not considering?