When my portfolio has risen about 50% i take out 10%. (5% in euro wallet and 5% in new ICO's)
My strategy is to take whatever, I just take whatever amount I think I should take out and that depends on how much profit I was able to make. Sometimes if there are signs that the market will drop after rising, I would withdraw everything I have and wait for it to drop and once it has dropped I will quickly buy in again, with either 50% or lesser than that (like I said before it depends) and wait for the price to rise again for another gain.