What a waste

Insurance...

Every once in a while I hear an opinion preppring is a waste of time. Well Maybe. Do you buy insurance in the hope of using the policy? No, you buy insurance so that in the event you need it, you've got it. Admittedly, if your 70 years old and preparing for an asteroid to hit the earth, there's probably a very very low liklihood that you'll need that spacecraft you've built in the back yard. .

Extremes 

On one end of the spectrum, one might say I need to be prepared to sustain myself with nutrients every day. I.e. I buy groceries and keep them in my house and eat them so I don't die. Admittedly this is on the very light end of scale. In the middle might be "I keep a generator so if the power goes out (which it does 3 times per year) I can power my furnace and refrigerator so I don't freeze and my food doesn't go bad". On the way out there end are some of the low probability things like a zombie apocolypse, or a foreign government has taken over the US, or "theres an ice storm that permanently freezes my country". 

Hobby vs Need

Well it seems to me folks look at prepping as a means to ensure personal safety or comefort. You might put that in the need category. Do I need to have the recommended FEMA suggested 72 hour cache of preparations? Thats closer to a need I'd say. At some point you might find yourself getting into these practices of self situational analysis and find some enjoyment in knowing you're setting yourself up for success. I'd certainly see many folks that have a bunker buried in their back yard are on this scale. At that point you might consider it as not only preparing for higher probability situations where you might call it a need, but finding yourself saying "this situation probably won't happen, but I want this widget, this prep, I want to be ready for it" where you're getting maybe into the hobby territory. But that's ok. Nothing says you have to only have to prepare for events that have a 95% probability of occuring in the next year. If you find enjoyment in it, do it!

It's Up To You

Perceptions vary from person to person on what level of preparedness you might want to have. Certainly those activities like buying food aren't a waste of time, I'd suggest the waste of time goes up in accuracy the more likelihood of the event your prepping for goes down. So, ignore the trolls, but also maybe keep a constant checkpoint in your head asking yourself "do I want to be prepared for this scenario, or is the likelihood or consequence so low that I don't think I want to or need to". Keep that there, think it through, maybe at the end you says "screw it I enjoy doing it and so I'm going to be ready for that eventuality!" again..... It's up to you.