Sell everything never. Sell enough to have extra fiat currency for extra expenses like bills.
If 1 BTC goes to 40k selling 30%.
After the massive of bitcoins price, I'm not expecting anymore with the price increase. Because it will happen suddenly and that $40k will be a good price to sell but I don't want to make myself upset again. I want to see the price first to reach at $3k and that will be my mark to sell.
Well you are very much optimistic about the BTC price I am not saying that it is bad but expecting such a high level that you talked of $40K is too much. There was a novel in my high school curriculum name The great expectation. Your this much expectation level reminded me the novel lolz. Anyway it is good but you have to keep yourself ready for any uncertain situation if occurred.