Like many other posters, in the past I've sold lots of stocks...

Like many other posters, in the past I've sold lots of stocks way too early and missed out on lots of upside. I've also held some stocks where the price has gone up and then come all the way back down again and I haven't sold. These days I sell progressively and this was worked well for me so far - for example if the price goes up say 75% I may sell say 20% of my holding, then if it goes up another 35% I may sell another 15% of the holding then if it goes up another 50% I'll sell another 15% etc. This has worked very well for me over the last year. Normally the stock starts retreating before I have sold all my holding and a number of times I have bought some of the stock back later once the price has retreated.