I think a NSB account entails ordering a certain quantity of product from Nike on a monthly basis. It's hard to keep ordering new products when you have old product (some of these shops have 5+ year old shoes still in stock) still sitting.
Also, I don't think Nike has a buy-back program with NSB accounts like they do with major retailers (FTL, FNL, etc.).
Maybe
@ATs Kicks can shed some light on this for us?
Depending on your Contract, Nike DOES make you buy New Inventory every month.
But, it just depends on the Contract that Nike made you sign, you were able to sign or just given by Nike.
3 Main Contracts, although their are others, these are the 3 Main ones:
1)You want to carry Nike SB, they will send you whatever THEY want(Everything mostly - Janoski's, Koston's, and Dunks sprinkled here and there(GR mostly, but sometimes will throw in QS, also including clothing); And takes a long while to be able to pick and choose your own.
2)You have a history of selling a large amount of inventory weekly/monthly(other brands - mostly sneaks, but they also count clothing), you had a previous contract and are STILL well established, or YOU just happen to know someone from Nike SB or someone whom you used to work with from another brand, who now works with Nike SB. You buy want you want and get to carry what you want.
3)Like the first, BUT mostly leftovers that other shops have not been successful with and Nike SB is wanting to push; This is sometimes a Testing phase for the shops.
Of course ALL Nike Contracts are very expensive and ALL Bills must be payed prior to ANY/ALL New shipments/inventory being sent out.
The bigger Shops of course are given bigger and better inventory, but some smaller established shops are also given perks - QS; although a very small quantity and normally not a full size run.
Yes, many shops get stuck with leftover inventory and have to eventually reduce and then try and sell, if THEY CAN.
We all know that not all Nike SB sells, even if it is 50% or higher off.
Nike HAS NEVER had a by back program, unlike other Sneak brands like Vans, ES, Huf, Adidas, etc...
Cons(they used to be able to send these back, prior to the Nike Merger.)
The local saying/slogan is "You bought it, You own it! No Returns!"
BUT, if you do have a Great Relationship with Nike SB and if the Inventory is still able at the Warehouse, Nike will allow you to purchase more, for example - De La's, Send Help II's, etc... Sometimes at a lower price depending on the Shops reputation.
Hope this helps...