Separate retail stock, professional-use supplies, damaged items, and quarantined items. Record the product, unit, quantity, location, supplier, and relevant lot or date information. A bottle count is misleading if several bottles are nearly empty. Use a consistent unit such as sealed bottles or estimated usable milliliters, and label estimates as estimates. Do not include questionable stock as available for service.

A simple planning model is expected use during supplier lead time plus a safety allowance. At four units per week, two weeks of lead time and three reserve units, the reorder point is 11 units. This is a planning trigger, not a universal safety standard. Check demand variation, delivery reliability, minimum order size and storage limits before setting the number.

Unit price alone hides freight, minimum orders, waste, storage and uncertain authenticity. Twenty units at $5 plus $20 shipping cost $120, or $6 per unit before other expenses. A larger order can have a lower unit price and still be a poor decision if items cannot be used in time. Verify suppliers, product identity and instructions; a substitute is not equivalent merely because the packaging looks similar.

Storage conditions and use affect product integrity. Follow the actual manufacturer directions, applicable rules and safety information. Track relevant dates and inspect condition; a product without a printed expiration date is not automatically safe indefinitely. Keep suspect items out of use while resolving uncertainty. Do not invent a single shelf-life rule for every cosmetic or chemical.

Compare opening usable stock plus receipts minus closing stock with expected use, documenting returns, waste and adjustments. A difference is a question to investigate, not proof of theft. For example, 15 opening units plus 10 received minus 8 closing equals 17 units moved out of stock. Identify which were sold, used, returned or discarded before drawing conclusions.