Loyal readers know that I believe Everyone Should Have a Wacom Tablet. Even if a tablet is your primary pointing device, it is always good to have a mouse as a backup. On each of my computers, I have a Logitech Wireless Mouse attached. You simply plug a small receiver into a USB port and the mouse will communicate with that receiver.
It does require a new battery every now and then, but you can use the power switch on the bottom of the mouse to turn it off when not in use. When I travel, I make sure to have this mouse with me just in case I have any issues with the tablet. It also can be more convenient if I’m trying to work in a tight space where there isn’t room for a tablet. At under $25 at Amazon, this is an accessory everyone should have.