Criteria for evaluation of sewing machines. Based on the study and monitoring of prices in Europe, the United States and England , communicating with collectors and societies of sewing machine collectors abroad, as well as contact with museums in different countries, I can say the following : 1. THE COST OF SEWING MACHINES DEPENDS ON THE RARITY OF THE MODEL, FOR EXAMPLE, IF ANY OF THE MACHINE MODELS ARE FOUND IN THE NUMBER OF 5 TO 20 COPIES IN THE WORLD. 2. THE CONDITION OF THE SEWING MACHINE, EXTERNAL CONDITION, TECHNICAL CONDITION, SHOULD BE IDEAL, THE SAFETY OF ACCESSORIES IN THE SET TO IT (FEET, NEEDLES, OIL, INSTRUCTIONS IN PAPER FORMAT AND OTHER ACCESSORIES), THE SAFETY OF PICTURES-DECOLORS, THE SAFETY OF THE PAINT COATING 3. ANY RESTORATION REDUCES THE COLLECTOR'S VALUE - BECAUSE THE FACT OF RESTORATION - (INTERVENTION) CHANGES THE DEGREE OF ORIGINALITY AND AUTHENTICITY OF THE SEWING MACHINE. 4. THE GREATEST HISTORICAL AND COLLECTIBLE VALUE HAVE SEWING MACHINES OF EARLY MODELS, PRODUCED IN THE MIDDLE OF THE 19TH CENTURY. AND BEFORE YOU PUT THE SEWING MACHINE ON THE TRADING FLOOR - IT IS NECESSARY TO CLARIFY EXACTLY WHAT MODEL YOU HAVE, WHEN IT WAS PRODUCED AND HOW RARE IT IS FOUND IN THE SALE AND ONLY THEN SET ITS PRICE.