I keep thinking of things. So one habit we have is to never only have one of things we really need. So if it is perishable we buy two unless they will spoil. I have a large freezer. I date things and rotate. This isn't time consuming. Just requires thought and a few minutes here and there.

Honestly, I would say being prepared is really all about thinking about the future and making a plan for when shit hits the fan. Priorities should be based on likelihood, impact, difficulty to solve. If something is highly likely but easy to fix, fix it. If it is highly unlikely but high impact but also very difficult to fix maybe you solved that later.

The anti prepper stuff shows dumb people preparing for unlikely things in extreme ways while ignoring likely things that have huge impact. Food for example. Guns over food for example. Why not both? Are you gonna steal food from your neighbour with your guns?

Another thing is when you have an event like storm or power outage what happens? Afterwards figure out what you could do different.

I don't divide my tasks by that category so I honestly don't know. If it is worth doing I try to do it. Garden season is here so I will be spending more time there but even that is mostly a weekend or two and minimal effort after. I try to be systematic in what I do and efficient.

Impossible to answer. It varies with the season. Not much of my time though. I think what you are asking is, is it worth my time? That is subjective to your risks where you live and your standard of living.