If what you invested in(bought) does have a good future in your opinion, it's better to sell some portion of it and keep the rest for the possible bigger moves up, it's sort of dollar cost averaging but instead of buying more when the price goes down, you're selling some every time price goes up.

Of course it's not a very smart move to not sell anything at all while you're up 3-5-10x, unless you don't care about losing the profit you got so far from that investment and you're okay with losing your profit as it can happen specially with shitcoins.