How not to make a mistake with the price when selling and not to overpay when buying

The main question in any transaction on the secondary photographic equipment market is **how much does the mileage cost?** Identical Canon 5D bodies A 15,000 frame Mark IV and a 180,000 frame Mark IV may not cost the same. But how to subtract wear and tear mathematically correctly?

Over the years of service evaluation, I have developed a proven formula for price correction depending on the exhausted service life of the bolt block.

Master's Formula: Base Market Price - Shutter Wear

Step 1: Take the average market value of a model in “perfect condition” (mileage up to 10–15% of the warranty period).

Step 2: Calculate the gate efficiency:Output (%) = (Current mileage / Official resource) * 100%

Step 3: Apply discount gradation:

Percentage of resource production	Condition Status	Recommended discount from average price
0% – 15%	Excellent (like new)	0% (Sold at the top market level).
15% – 50%	Good working	Discount 10% – 15%.
50% – 80%	Medium (significant impact)	Discount 20% – 30%.
80% – 100%+	High risk of valve replacement	Discount = Cost of replacing the shutter in the service + 10%.

Calculation example for Nikon D750 (resource 150,000 frames)

• A camera with a runtime of 15,000 frames (10% of the resource) costs ~**65,000 rubles**.
• A camera with a mileage of 120,000 frames (80% of the resource) should cost a 30% discount: `65,000 * 0.70 = ~45,500 rubles`.