We are away for a month and it always staggers me how much you can fit in these bloody panniers.
In pannier one:
2 x folding seats. 1 x wash kit. 3 x gas canisters. 2 x large towels. 3 x full dried meals. 2 x rechargeable (via usb) torches 2 x portable battery packs (all charged via the bike). Toilet roll, wet wipes, insect repellent, washing line, washing liquid, billy cans, spare cooker, eating utensils. First aid kit. And loads and loads of coffee!
In pannier two:
1 x Vango Banshee 300 tent. 2 x sleeping bags. 2 x inflatable pillows. 2 x Static Vee sleeping mats. 1 x small ground sheet/sun shade.
That leaves the top box for a few clothes and room to spare. When I first met our lass I told her, "If you ever need to put luggage in the hold of a plane or can't fit all your clothes on the bike we might as well finish now pet". She has never let me down. she is as they say, "A bloody good one!"