"Only invest an amount you can afford to lose."
Probably one of the most common advice I've heard when it comes to investing in bitcoin; and I've used it a lot of times too. But honestly, in our current situation where fiat is getting printed like hell, I started to use that statement less and less. It just seems that holding bitcoin is now totally necessary.
We must not get too emotional while investing in bitcoin. Despite all odds we still need fiat for our daily livings since its accepted and used in every corner of the world. I do agree with saying since its one of fundamental guidelines for every investment. There are stories of people taking loan to invest in crypto and end in loss.