I dont know if this has already been posted but ill post it anyway. Ive been using this for a while. When your bags are full both in the bank and inventory you can put your items on the auction house for huge prices. That is mostly done with items which have very low cost to be put on the auction house , like 1 s / per auction. That way you can save some of your items in banks and exchange the items whenever you need them with other alts. For example im playing with alt number one and i decide that i need more runecloth for tailoring. I buyout the auction from my main for 10 gold , and i get the gold back on my main afterwards. So it works as a whole account bank , or just a single bank with unlimited spots that can be used for a fee.