Like said before, giving first aid as a non-professional is generally not a huge concern regarding being sued thanks to Good Samaritan laws. Thank God.
Second, and I don't think it has been mentioned here before,
you should really make a distinction between a comfort-oriented first aid kit, and a lifesaving-oriented first aid kit. For a regular person minding their own business, honestly I believe
any decent first aid kit will have a bit of both. You won't ever carry your first aid kit if it only has tourniquets and chest seals (because you'll never need or use it), but it does you little good to try to fix a gunshot wound with band-aids and aspirin. Every good first aid kit has a bit of both, and you should choose what components work best for you depending on what you like, what you're most likely going to need, and what you know how to use.
Next point, there isn't any first aid kit on the market that is
perfect for you. You'll have to expand, reduce and compliment as necessary. Personally, I have a fully stocked
Ever Ready First Aid Fully Stocked First Responder Kit, Orange (Disclaimer, links are Amazon affiliate links. I tend to use them as a habit) at home, which I use as a "main" first aid kit, and use to stock my other secondary first aid kits as needed. My favorite secondary first aid kit is
ADVENTURE MEDICAL KITS Ultralight 0.5 Solo First. I never carry one on my person, but if I'm carrying a range bag or backpack you can pretty much bet I have one inside. It's a tiny waterproof bag that weights about an ounce that you can stash in any backpack side pocket along with a CAT. So basically I have one on me 90% of the time. The trick is to buy boxes of individual "doses" of everything (Like these
Wonder Seal Packets of clotting powder or
Alcohol Antiseptic Wipes), keep those in the main bag, and simply put 2 or 3 mini doses in the smaller kits. That way you can have dozens of "fixes" in a tiny bag. I use my first aid kits (as a normal civilian) pretty often, although ironically never on myself.
Regarding IFAK's, honestly I've bought a "commercial" one once and decided to never do it again. The
AR500 Armor® Tactical EPIK (IFAK) is just a loaded
Condor Tactical Sidekick Pouch. Just buy a
Condor First Aid Pouch in the size you want and fill it yourself for cheaper with what you want to carry and what you know how to use. I use the
Condor Rip-Away EMT Pouch on my SHTF plate carrier, the
Condor Tactical T&T Pouch as my serious range bag first aid kit. Then I just fill em up myself. But honestly my IFAK's are more as a hobby or a "just in case". If I had to choose only one, I'd take my Ultralight kits in a heartbeat.
Training is paramount of course. I personally did a 40 hours hands-on training, 40 hours theory training which is the best course I've ever done (certified lifeguard training). After that I've done more CPR courses, First Aid Courses, or or short preparedness courses than I care to remember, besides articles or Youtube videos to keep it fresh. I definitely appreciate knowing that I have first aid skills for most frequent injuries and issues. The downside about it is having friends come over whenever they want free first aid after minor but ugly incidents.
Last time I used my first aid kit it was on the ugliest case of slide bite I had seen, on a friend, who was bleeding quite a bit making a mess in an indoor range. Wound Seal + Bandages +
3M Steristrips saved the day (it was almost funny to see the Range Officer standing by cluelessly while I gave first aid). I certainly recommend multiple packets of the smaller haemostatic agent (the Wound Seal above) rather than simply keeping Celox, which you will rarely if ever have an excuse to use. Wound Seal is useful to me at least 2 or 3 times a year.
Below you'll find a file I wrote for myself as a checklist for the components I like keeping in stock. Yes it will seem pretty exhaustive and overly complete, but it all fits in the first responder bag linked above that I just keep stashed in a closet. I keep that document in my first aid kit since it also provides me with some basic tips, advice and use suggestions. It explains what almost every serious component in the kit is, and how to use it. In the document you'll also find what I stock in my mini first aid kits, all of which surprisingly fits in my
ADVENTURE MEDICAL KITS Ultralight 0.5 Solo First.
By the way, having some fun
learning to use a Nasopharyngeal Airway on yourself is a must-do for anyone learning serious first aid.
My eyes still tear up remembering it...
Of course, typical disclaimer that all of this is my opinion and any information is for informational or entertainment purposes only. Sigh.