It’s very sensible to have things to tide you over in an emergency. We have enough food that we could survive several weeks to a month if we needed to. We have a generator. We have a water purification system and tablets. We have multiple gas cookers that we could cook on if a power outage. We have a solar charging unit (we use it for camping, but would also be useful in an emergency). Not because we’re preppers. We’re not. Because we live rurally and we’re sensibly stocked up. We have all these things for reasons totally unrelated to thinking the global order is about to collapse.
I used to live in an earthquake prone region and had to take an earthquake preparedness class for work. It’s not even stockpiling. It’s things like everyone in the house knowing where to turn off the water and the gas, knowing where the torches are kept. Having cash was a big one. I don’t use cash, but we were told to always have a stash of cash in coins and small bills so that if the power goes out, you aren’t relying on card payments or a cash machine, neither of which will work.
If you take essential medicines, order enough to keep a small extra stock. I have several health conditions that require me to be on medication daily for life. I could survive, miserably, without some of it, but one is absolutely essential to keep me alive. Like insulin. We are told to always have a 3 month supply. I also have several sets of emergency rescue medication. This is really helpful because a few years ago during COVID one of my meds experienced a global shortage (they reduced manufacturing due to making something COVID related instead). It became very hard to source. Because I had several months supply, I was okay, but lots of people really suffered.
I think 3 days personally is quite short though. If shit hits the fan, you’ll need more than 3 days. 2-3 weeks is probably more sensible in terms of food and the most basic stuff you need to live. Like I said, I’m not at all some nutjob conspiracy theorist! But I have lived in areas that experience a lot of natural disasters and in areas with high risk of terror attacks where we’ve had to shelter in place. It’s just sensible.