When life is so unpredictable how does one know what their future karma holds?
There’s really no such thing as “future karma”, that’s taking karma and making it something magical. Karma, understood correctly, is just an abstract way of talking about the cumulative effects of past actions. So for example, if I have lied to my colleagues at work repeatedly about how well a project is going, and the deadline comes and I’m not ready, it will be obvious to all that I’ve been misleading them. That has obvious career consequences. Karma is not magic. There is no cosmic scoreboard where your points are being added up and so forth. It’s just a way of talking about cause and effect.