So my question is when do you consider the best time to sell your bitcoin or is it better to just save it for a while considering the constant rise in price.
As on today, bitcoin has not yet reached the peak of its price and hence it is not a good decision to sell your bitcoins. Bitcoin still has a lot of potential to go up in near future and the best thing to do is invest as your pocket permits. No other investment asset would be able to give you that much return.
So the best thing to do is invest and hold. Nothing else will give you the desired return than this. Bitcoin is at 4k USd now and I believe a little correction will follow soon. So buy at the dips and hold for better. Just don't loose your patience.