Right, I had individuals in mind re my question. Mostly mine are legacy holdings, msft, vod, and a couple more. I too mostly hold indices, for the longer term. I did sell 1/2 my veiex and vgsix before they zoomed, and 1/2 my vod at 22 (but put the proceeds into vstmx). Now the remaining half of vgsix and veiex has ballooned to where I probably ought to dump some again, but find it hard to sell! :)
There is some research somewhere that says if in doubt, sell 1/2.
I am interested in how well the magic predictors do with trading, taking taxes into account and comparing with buy and hold over some time periods. Seems to be a lack of posting about that.