Knowing what you have is as important as knowing where it is. Every pre-made bag has its' pockets, zippered compartments and velcro flaps. I changed handbags last week and I can't find anything. A bug out or bug in bag is more important that the file of receipts I keep in my handbag, so I owe it to myself to know which flap hides the glow sticks, which pocket has the multi-tool, and where is the water filter?
I recommend for the price and the fact that you will always know where your stuff is if you put it together yourself. Home made kits are the best kits. They can be as fully kitted as any ready made kit or they can be made for specific tasks. You can make a fire kit, a food kit, a first aid kit, a hunting kit, a tracking kit, then keep a bigger bag with all the individual kits inside. They are great gifts, but once you give one, if you see it again, don't frown when you see it 'remade' to fit that person's needs.
When you get familiar with your bag and it's contents, take a minute to think about your second in command, your spouse or better half.
If you are separated for any reason, even if for a few minutes, the other half can start setting up the home if they a.) know where the gear is and b.) know what's in the pockets, flaps, cans or bags.
Two can survive better than one. Well kitted and ready, two can survive almost anything, together.