I like to move my keyboard around depending on what I'm doing (gaming, editing, typing, browser...) and I do use different sizes of keyboards depending on my mood. However, I always prefer to have my mouse placed right against my keyboard. With a regular mouse mat, I need to move the mouse mat every time I move/switch the keyboard. With mat that is big enough to go underneath the keyboard I can move my keyboard freely without having to adjust the location of the mouse mat at all.