Considerations in a scenario where you do not plan to leave the urban/suburban/small-town environment where you currently find yourself.

Vermin
In a disaster, humans will of course be looting/raiding food stocks; but so will mice and rats. Without humans to constantly guard foodstocks, rats and mice can easily chew through most retail packaging. For example, in the wake of a super-flu epidemic, there would be lots of unoccupied homes, with pantries that were more or less stocked with food at the onset of the epidemic. But without humans to set traps and bait….mice, rats and even squirrels would quickly chew through most of the packaging in most pantries. In fact, any food not stored in a specifically rodent-proof container will probably have been eaten within a month or three.

Danger from falling or being crushed
Many survivors in a disaster who have “hunkered down” will find themselves entering burnt-out or collapsed buildings. There will be things you want in the upper stories of buildings; but many of them may have been damaged by the event itself (earthquake, act of war, hurricane). Other buildings will have been gutted by looters, combatants, and wildfires.

Danger of leg injuries from breaks & sprains
Life in a (formerly) human community will involve walking over lots of broken glass, fallen masonry and drywall; climbing over broken fences, or navigating piles of goods damaged by looters in the shops. After the first summer, grass will begin poking up through cracks in the pavement, making us look down while we walk. A clear, even path will no longer be an assumption we can make. Heck, no one will be there to sweep the streets and walks; so piles of leaves will be an issue after the first autumn.

Dust
War is dusty. So are earthquakes and any kind of demolition. Not to mention any kind of terror attack involving powders or dusts. Nuisance level masks are inexpensive and disposable, because there is no widespread need for them, right now.


Danger from wild animals among the ruins
From animals escaped from zoos, to starving and desperate house pets, to packs of wild dogs, to rural animals moving into the necropolis to fill the now vacant niche of “apex predator.” You could encounter anything from a pack of wild dogs, to herds of feral hogs, to some drug-lord’s pet tiger. As deer and rabbits make their homes among formerly human areas, the predators that feed on them are sure to follow. You’ll need to guard your food stockpiles, and think about how you hang game.

Danger from latrines
If you have a group of even 4 people, you’ll have to plan your latrine carefully. Feces attrack carrion-eaters. Latrines breed bacteria and parasites. And something that modern folks are not aware of is that at least in North America, black widow spiders gravitate to the undersides of toilet seats. In fact, up until WWII most Black Widow bites were to the groin area…..

Useful, though overlooked items
Mouse traps, rat poison
Rodent proof food storage
Dust masks
Work gloves
Work boots
Head protection
Eye protection
Bolt cutters
Chain
Para-cord
Come-along (a kind of manual winch)
Fireman’s pick or spike
Sledgehammer
Shopping cart for wheel-barrow


Some of the above items take up space, but bulk is less of a concern for those preparing for survival-in-place.

If you really plan to bug in in an urban environment, I suggest a small oxy/acetylene torch rig. Learn how to use it first though. It can be used for welding/fabricating(welding metal doors shut among other things) and/or cutting(like if you need to cut your way into a locked gun store or something). Much less labor intensive than trying to smash your way in. I do a lot of A/C work, so I keep a small rig in my truck. My vehicle is my "bug out/in bag of first resort".