From the start of the “modern” collision shop in the late 1940s up through the 1970s, body shops, as a business, were fairly crude by most standards.
They needed little in the way of equipment - perhaps an air compressor being their most expensive item. With some sanders, body files, a few spray guns and a fan to remove paint fumes, they were good to go.
The business and accounting side of things wasn’t any more sophisticated. A shop owner bringing a year’s worth of receipts to their accountant at the end of the year enabling them to calculate taxes passed for accounting and business management. Owners didn’t know from week to week if they made a profit or not, or if their business was going forward or backward. If there was money left in the checkbook after payroll, it was a good week. Accounting and management tools for the collision repair trade just did not exist – and even if they had existed, nobody knew how to use them or what the number meant once they were calculated. Most owners came up through the ranks as technicians. They could write an estimate (albeit most did not know if the repair would be profitable or not) and repair a wreck, but were woefully inadequate in the business management department.
In 1974, industry pioneer Denny Kiyohara started an accounting service and focused on body shops. The only shops that were anywhere near organized enough to use his services were dealership body shops -- ones used to shuffling a lot of paper and tracking numbers. (Anyone who worked in any dealership department, even then, knew it was a numbers game). Seeing a need, Kiyohara developed the first computerized accounting system for body shops; the Automotive Repair Management System (ARMS). Eventually, he created a computer system to handle what had previously been done on spreadsheets. In 1976, Kiyohara started with 13 shops, networked together, and started aggregating and sharing numbers. It was the precursor to what would later be known collectively as “20-groups.”