When you only carry you single sword or spear or whatever, things are rather easy. However having a good inventory system is not a bad idea once you get enough....um inventory to carry around.
Its not just about having scabbards and quivers and pouches and bags...its about placing them all in a way that makes it easy to carry. A lot of people ignore this and then suffer from their mistake. Truth to be said first you DO need to figure out what you'd be bringing to the fun or to the fight...and then figure out how exactly to carry it. Still, it needs to be done.
By all means if you can carry around 2 PKMs and a dozen kalashnikovs like this gentleman, be my guest.
Things to consider.
3. Extra gear.
How many and what kind of weapons do you bring? How easy to reach you want them?
2. What armor do you bring? How heavy it is and how will it fit with the weapons?
3. What extra gear you bring? Water skin? Pouch? Coin purse? A bag for food and other things? When you put everything at once its one hell of a puzzle.
Always keep in mind that there is a limit on how much you can carry. Its not just about comfort - you only have 2 arms after all - unless you've learned how to hold a sword with your toes, extra weapons won't help you.
After you've picked the gear for your current task. Its time to pack up. Useful thing to have is at least 2 spare belts. You can't have everything resting on one.
Now let's give an example.
On this photo I have a shield on my back, a coin purse, a sword, quiver and bow all set in a way that leaves my hands free.
When deciding how to carry - the heaviest and most cumbersome item was the shield so it went to the back. Quiver went to my right hip and sword to the left one. The bow is held in a hip holster like this one.
So much for point 1 - weapons.
Now I can march around all day. There is nothing to hold in my hands (like a spear or a shield) and everything is situated in a fairly stable manner. I don't have to worry about dropping anything.
Why is the armor relevant though?
Well due to the armor, I can't try things like stuffing a knife in my boot and my pockets are hard to reach and thus not suitable for game relevant items(still good for keeping my keys).
So when it comes to part 3 Extra gear - I have to get a coin purse, preferably that and a pouch to carry things that I will have to use often.
I can even take on a few more items. There are options too - drop the shield and the quiver can go to the back, leaving my left hip free to take, say a full stack of throwing axes? Or the bag with the food? Or something else? How about a mace strapped next to the quiver? Decisions decisions...