Assets fall into two groups
Tools and Equipments
Tracked individually with a unique ID (barcode or serial number or asset tag). An asset tracked with a unique ID counts as one item.
Bulk & Consumables
Tracked in group by quantity. Assets tracked by quantity are counted as one item for their entire group as all of them have the same barcode. So if you are tracking 100 shovels, they are counted as 1 and not 100 as all shovel will have same unique ID.
If you exceed plan quantities, you are able to upgrade to higher plan.