This decision depends on your location and whether you are lifting weights competitively or not. If you live in the US, it’s easier to buy lbs plates because that is the standard measurement of weight in the country. If you plan on competing in the Olympics or other weight lifting sport events, you should buy Kg plates. What’s awesome is that you can find Olympic weights for sale in Kilograms if that is what you prefer. They start from 1.25-25Kgs.