Harvesting pears is a little different from most fruit. Most fruit is great fresh off the tree, but pears ripen best off the tree. Pears left to ripen on the tree ripen from the inside out giving them a grainy texture and easily rotting. Harvest pears when they are full sized, the dark green skin color has turned lighter, the skin has taken on a waxy feel rather than pebbly, and the fruit separates easily from the spur. Cool the pears to 32-40 degrees F. This is an important step. Once cooled, they will store well and you can remove individual pears and allow them to ripen at room temperature. The good part of this is you can always have perfectly ripened pears. These 2 articles give additional information, When to Pick the Perfect Pear https://extension.oregonstate.edu/gardening/flowers-shrubs-trees/when-pick-perfect-pear and Picking and Storing Apples and Pears https://catalog.extension.oregonstate.edu/fs147/html.