i think you should spend some and save some for emergencies and that is why you can do that but you need to think over the fact that you can put some money in an other investment and have some money when that goes wrong.
That is the point. Actually you are trying to explain dividing rule. That will be so better if you divide your bitcoins, half for your savings for emergencies and other household needs, other half for investments. Second half is much better in all respect to enhance your bitcoins more and more.