Keeping up with stock is always an issue with all online sites. The issue being no one ever knows what a customer may want or the qty required. It's not the same as a walk in store where you buy what is on the shelves and the store manager then knows what to reorder. We simply don't know whether we should have 1 or 1,000 available.
Our restocking method is based on the quarterly sales over a 3 year period. If we sold 30 units of product "A" during the 3rd quarter of each of the last 3 years then we will try to maintain a stock level of 30 units of product "A".
Reordering periods: Most of our suppliers require a minimum order amount, as soon as we can reach that goal we place our orders for those suppliers products.
A lot of times a product will show O/S or Low Stock, however it's already reached our reorder level and is either en-route or already here and not updated on the site yet. Which is why we have the notice to contact us and we'll gladly check this for you.
You can still place an order for the O/S or L/S flagged items, if the item is here we'll of course ship it immediately, if it's enroute or will be here within a day or so we'll hold the order until all items arrive.
For some items we don't know when they'll be delivered to us, for these items we normally contact the supplier and get a date from them, if they don't have a date then we'll cancel that item and issue a refund or adjust the order total to reflect this.
Backorder items: We try our best to never have items on B/O as this most always results in extra costs and confusion with keeping B/O ordered items going to the right order. Normally if an item is B/O this means it's O/S from the manufacturer and may be weeks or even months before they make more.