Stock Maintenance

Stock Maintenance

Hi,
Has anyone had experience with managing inventory and stock levels, and replenishment?

We have the potential of having around 4000 units of 1 item. e.g Item A - 4000 qty.
Adding this item 4000 times is impractical, and defeats the idea of stock management.
How do we adjust stock according to stock levels.

Any advice appreciated.

Regards