Where should I keep it?
Somewhere clean, dry and convenient to get to in an emergency (Not buried in a closet.) I don't recommend a garage because of the temperature fluctuations. The basement is fine if it's clean, dry, and easy to get to. A hall or coat closet might work. Some families and households have each member store their bag in their own room. (With kids you'll probably want to oversee this concept.)
But you said I need more than one bag!
That I did. Keep something at work. It can certainly be smaller, if you like. But an emergency is as likely to happen while you're at work, and you want to be ready to stay or go. A friend of mine tells a funny story about kissing his wife good-bye and going to work knowing that impending flooding would strand him at work for the next two to three days. When he gets to the part about wading through flood waters to get from his office to the convenience store across the street because he was hungry, I stopped laughing. He needed a go-bag at work.
My sister called me soon after starting her son at daycare. In the first weeks after compiling these kits, she had unexpectedly used several items from his daycare and car emergency go-bags. She needed an extra bottle (when one broke), a jar of strained prunes (You know what that was for.), and the hoodie from the car (during an unexpected cold snap). She replaced them all immediately, of course, but she was thrilled to be able to solve problems so conveniently.
I have frequently used the extra clothes in my office. I try to balance the outfit I keep at work. It needs to be dressy enough that I can get away with wearing it when I spill coffee (or mustard) down my front. But it needs to be comfortable enough that it's worth changing into in an emergency (like bad weather).
Keep something in the car. I highlighted a news story last December where hundreds of people were stranded in their cars on icy highways. Your four wheel drive won't do you any good in a traffic jam. Once you're stuck in traffic you're there, no matter what you're driving.
When is my go-bag good enough?
Remember the list of risks and likely events you made a few days ago. If your bags (and their location) suits each one of the risks you identified, then be done, Go-bags (like any project) can be overwhelming and grow into a monster that you want to get away from. I constantly tweak my supplies and ideas. That may make you crazy. When you're done and you're happy, put it away. Know it's there when you need it. (But don't forget to get it out next year to check over.)
This Series' Links
Functional Friday: Go Bag Part I - The Need
Functional Friday: Go Bag Part I - The Purpose
Functional Friday: Go Bag Part I - The Bag
Functional Friday: Go Bag Part I - The Basic Stuff
Functional Friday: Go Bag Part I - What's Next?