Inventory turns measure how often stock is sold and replaced in a year. A low figure means cash is tied up in parts sitting still.
Stock is cash
Every part on a shelf was paid for and has not yet earned anything. It is working capital in a form that cannot be used for anything else.
The right lever is mix, not level
Cutting stock across the board raises turns and causes stockouts, which cost more than the holding did: a job delayed, a second visit, sometimes a lost customer.
The improvement comes from separating the parts that move from the parts that do not, and holding the two differently.
Fast-moving parts used constantly should be held in depth. Running out of these is expensive and holding them is cheap, because they turn quickly.
Slow-moving parts ordered as needed. The delay is tolerable precisely because the demand is rare.
Dead stock — parts that have not moved in a year and will not. Holding them costs money for nothing, and the money spent on them is already gone. Selling or returning them at a loss recovers something; keeping them recovers nothing.
Where it accumulates
Over-ordering for a specific job and keeping the remainder, superseded parts kept in case, and bulk purchases taken for a discount that exceeded what could be used.
The last is worth checking. A discount on a quantity that takes three years to consume is not a saving.
Counting it
Turns calculated from a stock figure nobody has verified are arithmetic on a guess. A physical count, at least annually, is what makes the number real — see inventory.