[Lord Azagthoth]

For kit, boxes, etc. with expandable gear in it (e.g., medical kit, bycicle tyre repair box) I let them roll against the HT of the kit or box. If the roll is a success, you can use the kit to help a victim or mend a tyre and the HT drops by 1.

To replace items separately, a +1 to HT costs 10% of the original price of the kit or box.

Or when a kit has only a few charges (e.g. a bacta pistol with 5 ampoules of bacta), it's easier just to subtract an ampoule after usage.