I don't know about once in a lifetime event, in retrospect I could name a number of stocks that "if only I'd brought them then". But I'm sure most of us have played that depressing game. 

To find a once in a lifetime stock, well you need to be insanely good at reading the tea leaves. I mean I purchased $Citigroup(C)$ And $Bank of America(BAC)$ last year during the banking crisis. They were both super cheap so it was a no brainer. They are both up over 50% annualised as i write this, which is nice. But then other people write how they are up over 300% and my excitement kinda goes flaccid. 

I mean I have had a few once in a lifetime experiences. In the late 1990s and early 2000s The New Zealand government privatised a number of government infrastructure companies. The first IPO I put $3000 in but it was scaled back to $1000, but upon listing my $1000 went to $3000 in days. Next ipo, I got clever. My son had just been born like 1 month old, he got a tax number and brought $1000 of stock, I know clever boy right! I brought $1000 and my wife was also buying $1000. Again that IPO also tripled over two weeks. two others I did the same with, they only doubled. But gave us the deposit on our first house, and a trip to see the grandparents of our then family of 4.

In retrospect, maybe we can look back on a stock that goes to the moon, even Mars In a year or so. But I'd suggest the odds of that are not much better than winning lotto. IPOs can be the exception, but they need to be massively oversubscribed, and be huge, like instantly enter the top 10/ top 50 index, in my experience. So that was a once in a lifetime experience.

Instead of the once in a lifetime, I'd like to have a consistent strategy, that really works. Like many i benchmark to the s&p 500. So I want to outperform the s&p so at least 10% returns. As my investment strategy improves my goal moves higher, 15% this year for example.