I thought I'd put a question out to ETers - do you have any ideas or proven methods for when to sell excellent growth businesses? So far my method was to sell half once they are no longer cheap, and the other half once they appear expensive. But especially in 2010, this has been shown to miss out on massive potential gains later on. I also had a similar experience in the 2004-2007 period - nice gains, but could have been much bigger if I had held longer. And it's not just bubble gains either - several of these types of stocks have justified their previously 'expensive' valuation by blowing away earnings estimates. And I don't want to just take a perma-bull buy and hold approach regardless of valuation - because valuation does matter ultimately. I'm talking about stocks like CMG, NFLX, BIDU, and so on. Back in late 08 and early to mid 2009, these were at attractive valuations e.g. moderate PEs, with excellent long-term growth prospects, strong balance sheets and cashflow etc. Now they are very highly valued - 45, 70, and 83 times earnings respectively. How high a valuation can be rationally justified for the disciplined growth investor, before he MUST sell even the most attractive growth businesses? Any suggestions for how to hold on longer, whilst still retaining risk control and a sell discipline?