How about IAD? (It all Depends?)
I'be been known to pack in a Coleman two burner stove, sausages and beer for a full moon October-fest themed hike...
but that may be overkill for the 3.5 mile hike on well populated trail for normal people. :)
For a short hike on a well populated trail, esp one I know well, a day pack with water, snacks, and a light jacket is about all I take. If I am feeling esp saucy, I may even hike in comfy cotton cargo shorts! :D
For more ambitious hikes
, often off trail and above tree lino, esp solo, the kit is not far removed from my backpacking kit: Warm hat, gloves, shell mitts, etc. etc. etc. Just no shelter and no sleeping bag.
SOOOO..if I am hiking the Mummy Range by myself, you better believe I am prepared. If I am taking a stroll to the Royal Arch in town (3 miles r/t), I am more likely to pack a little libation rather than the ten essentials. :)
I threw together this basic list a few years back for general mountain hiking. More than foothills, on trail and in three-season Colorado weather when the weather forecast looks good:
Modify it as appropriate.
Typical for me, it does not list specific gear, but rather *type* of gear.
Conservative, but people new to the outdoors tend to like/need basic, solid advice.