A long time ago I used Logitech’s trackball line — the much-praised M570. For a while it was my daily driver; I bought several of them and even swapped in a fancier microswitch. Then… at some point I just gradually stopped using it. Maybe I got tired of cleaning the ball every day, or maybe it was the lack of Bluetooth, which always meant giving up a USB port — either way, “trackball” quietly dropped off my peripherals list. Later I heard Logitech had put out a new trackball with some kind of electromagnetic scroll wheel, but the price was absurd. Then came the M575. It’s the M570 with Bluetooth added and a slightly reworked shape, and that seems to be about it. Filling in the old model’s Bluetooth gap took Logitech at least five years. Impressive stuff.