Comment by throw0101c

> […] etc at the Internet bubble top then you would have missed out on huge gains since then.

Only if you never repurchased.

Or you could DCA out: have a standard policy that no single stock can be more that x% of your portfolio, and as any one gets above that limit you crystallize profits. It's no different than having a 60/40 portfolio and rebalancing your equities if they get >60%.

I lean more towards passive and (total) market index funds, and just riding the roller coaster, as anything else is fairly either impossible or too time consuming:

* https://ofdollarsanddata.com/even-god-couldnt-beat-dollar-co...