Welcome to ETS Suzie!

I won't rehash the previous comments. (I think I'm in agreement with them all.) Personally, our BOBs are constantly being changed and adjusted. You'll find there are as many suggestions for what to put in your BOB as there are leaves in a forest.

Other than your most likely bug-out scenarios, three very important factors to consider when you're figuring out what to put in it are who you'll be with, your climate and your skill level.

Who you'll be with is significant. One or more physically and mentally able adults are going to travel much differently than a family with young kids or elderly members. Your needs, and hence your gear and method of transport/carry, is going to be significantly impacted by the composition of your group members.

Here in Ontario, we get 3 types of weather: hot (summer), cold (winter) and kitchen sink (spring and fall). I adjust our BOBs based on the worst expected weather for whatever season we are in, keeping in mind that cold & wet and hot & dry are deathly mixtures. Water, clothing, shelter and fire are my top four priorities. In addition to Cody Lundin's words of wisdom about keeping our body's core temp or 98.6, I also keep Bear Grylls' "PRWF" (Please Remember What's First) in mind: Protection, Rescue, Water and Food.

Someone else has already suggested practice and I second that whole-heartedly. Know your skills and know your gear. It's true when they say that the more you know, the less you need. Don't buy into the minimalist/ultralight philosophy if you don't know how to build natural shelters or fire, for example. Likewise, don't expect to hump 300 pounds of gear on your back while on foot.

Good for you for getting started! Remember too that the only way to feel confident with what you pack is to get out there and test it!