I have the older version of the E-310 which I bought to replace a competitors grill that lasted about 3 years.  This Weber is now going on almost 7 years.  I grill about 42 weekends a year.  Each time is usually a significant amount of food so we have leftovers for the week.  We live in the Houston area so it is more humid than many locations.  The grill has held up very well considering the amount of use.  I have replaced the burners and flavor bars once.  I also replaced the grates as the ceramic-coated steel ones still rusted badly after about 4 years.  I replaced with the Weber stainless steel version grates which seem to be holding up very well.  Everything else is still trucking along.  Looking forward to investing in a new one in about 5 years or so.