How often must a tractor be serviced?

Answer 1

http://www.google.com/webhp?source=search_app#output=search&sclient=psy-ab&q=How+often+must+a+tractor+be+serviced%3F&oq=How+often+must+a+tractor+be+serviced%3F&gs_l=hp.3..33i29i30l2.3069.3069.0.3633.1.1.0.0.0.0.140.140.0j1.1.0...0.0...1c.1.14.psy-ab.H1m8Ra3srvI&pbx=1&bav=on.2,or.r_qf.&bvm=bv.46751780,d.aWc&fp=f65b07ee42b869c5&biw=711&bih=453