What size mouse pad should I use for low DPI vs high DPI gaming?

For low DPI (800 or less) with arm aiming, get at least an 18×16 inch pad to avoid running out of space mid-flick. For high DPI (3200+) wrist aimers, a standard 12×10 or 14×12 pad is fine. If you switch between styles, go larger to be safe.