I was using the L3700su yesterday... just has to pick something up and put it in the back of the dump truck. I noticed how low on tread my front R4 tires were.. the tears are fine but the fronts only have about 1/2 of lug depth left on them. They are original and I guess about 8-9 years old now. Tractor has about 300 hrs on it with a mix of dirt and asphalt use. If I recall correctly, my skid steer would use up a set of tires every 250 hrs or so under mixed use.