For me there is not much difference, for within 15 min depending on the vehicle I have at the moment will depend on how much I will take. If they say that you might get back into you house in a few days... pack for a few weeks. 😮

have to redo and scale down our bags, they are holding way too much and weight is insane, not to mention it is 4'wide with sleeping bag/blanket roll tied on it...lol got carried away when we bought larger bags at Bass Pro because others were to small, now I need a happy medium

Unless your situation requires a super fast and light solution, i'd say definitely a bug out bag - who knows if 72 hours could turn into a week or more. Whenever I hear 72 hour kit I think of those cheap ones made in China - so If you decide to make a scaled down bug out bag as a 72 hour kit, put it together yourself with useful gear that lasts more than 12 hours 😀

... an afterthought, a good 72 hour kit could be useful - something you could show guests/babysitter at home "in the event of an emergency or power outage", instead of bringing out your finely packed BOB.

We all know the differences between the two kits my question is in which situations would which bag be better is it even worth it to have the two kits?

The concept behind it may be different, but it's essentially the same bag for me. I don't see a point of doubling up on certain items just so I can label one BOB and the other one 72 hrs kit. That said, the bag I carry in my vehicles, Get Home Bags, are quite different. They are mostly clothing to change from a suit or like clothing into something that would allow me to work on the truck in the elements or to do the trek to safety. The rest of it is small survival items, a bit of food and water for a day or two.

our BOB's are more like a week or more bags

My BOB is a modified 72 hour bag. I have food for three days and water for one, and have added the tools I need to get/purify more as well as a trauma kit, sil-tarp, my trusty maggot and 20m of para-chord. The idea is to add duration and allow for pick up as you progress. Three days of food doesn't take up a lot of space, I use MREs in their broken down form (saves a lot of space), but the water adds a significant amount of volume and weight (two litres is two kilos).

I'm still struggling with the ammo, though. In my Go-bag I used to keep an extra 100rds for my primary weapon and 50rds for my secondary, but the nature of bug out situations here in Canada are drastically different from what we were prepared for/had experience with while deployed.

-S.