Well, not knowing what horsepower tractors you are looking at but there are a few 3pt attachments that can get very heavy where that added weight could be very important. Normal finish mowing, box blading, blading, tilling shouldn't cause a problem as these attachments generally arent over 1600 pounds. Some of the heavy duty rotary cutters can get around that weight or heaviers and there are some other attachments that may get above that 1600 pound weight, but not knowing what pto horsepower your dealing with, I couldn't say for certain. Many of the much more knowledgable members may be able to help you a little more.