Bitcoin investments is a very promising investment which although seems to be of long term returns.most persons are not patient enough to wait till the value of Bitcoins rise significantly .
Soo in general how much should one invest in Bitcoin should it be "how much you can easily invest without stress " or "as much as you can invest at all cost"
Although I am aware it isn't a do or die affair
It's a very nice question and the answer to your question depends on how much you have and whether investing a certain amount would affect you financially. If you have an extra 1000 dollars or more divide it by 10 and invest it in Bitcoin at various price ranges.
For instance if you have 1000 dollars to invest divide it by 10 which will provide you with the chance to invest in 10 different ranges. The first range should be at 29,000 dollars and the second range should be at 27,000 dollars and continue investing in this pattern. If your order get successfully filled at those ranges then hold onto them for at least 4-5 years.