My wife Lena paints. Oils, acrylics, watercolors. Flowers, landscapes, the occasional cello or violin from her music series. Each painting is its own thing, photographed and listed on her store at artbylena.com . The catalog has crept past a hundred and twenty pieces and keeps growing. Last spring, two weeks out from Mother's Day, she decided to run a 20% sale on the flower paintings. The right move - flowers are what people buy for their mothers. She opened the WooCommerce admin and started editing each painting in the Flowers category. Set a sale price. Set a start date. Set an end date. Save. Next painting. Save. Forty-something paintings later her shoulders hurt and the spreadsheet she'd opened to keep track of the original prices was wrong in two places. On the day the sale was supposed to end, she had to do it all again in reverse: open each painting, clear the sale price, save. Another evening of clicking. She did this once. She is not doing it again.…