OK here goes......
I have a fair few bergens and packs of various types and sizes, they are used for different things and jobs, this may take some time
Smallest first.....
1. I have one of the original Camelback MULE packs which has a 3 Litre bladder and about 1 litre of space but with the pockets on it you can fit a large amount of kit for the size
2. Bumbag which has 5litres of space but also 2 side pockets to hold kit/water bottles (this and with my mule is all i need for a good days bimble with lots of stuff)
3. A lightwieght running pack which holds a 3litre bladder and about 20-25 litres of space has two hand zip pockets on the belt bit to hold odds and ends easy to hand.
4. A green 30l munro sack tough and hard wearing but hardly used nowadays but still got it. single main compartment and a small lid pocket on it.
5. A NI issue pack, my main work bag hold a lot of kit, but can use it for everything from a few hours worth of kit to upto a week worth (summer kit) without any extras only the basics
6. A Osprey 38 litre sack (a very new purchase) mainly used for when civi walking (planning on doing the coast to coast with it). Holds a huge amount of kit got loads of feautres and loads of hidden extras and pocket, really a well thought out bag and tough will hold well over 38 litres that is says.
7. An all arms bergen, the old combat handbag

used mainly when working out of a car or to hold various projects and kit (trying to keep my tidy is a ever increasing job)
8. lowe alpine 70+10 Alpanyo bergen great expedition bag or for long distance walking when carring alot of kit, I have used it on the pennine way and the west highland way, still ok as its green and black.
9. PLCE shortback Bergen in DPM my work bag that keeps my exercise kit (SOP) packed and ready to go at all times. gets used alot but exclusively for work.
10. PLCE longback bergen in green, my new long term bushcraft bergen for long trips, working on the contents but when finished will be packed and ready to go at a moments notice
In additions to the bergens I have several set of side pouches including a couple with the yoke used to hold various bit of kit for when needed but a couple hold desginated kit for when needed so only have to strap them to the side and then already good to go. I also have a medics pouch which holds my team medics kit and other kit pouches which hold NBC and bivi kit too which can go into the bergens or get strapped to the sides. I have various webbing systems too all used for work from normal webbing through chest rigs (got a bout 3) through to assault vests (only 2 of them) and an old COP vest too which I could use for kit too........
Something tells me I have too much Kit