We bought our Signet 320 six years ago and it still works as well as the first day we used it.  We live in the northeast,right on the Canadian border in northern NY and grill year round.  The grill is used 2-3 times a week during the summer and maybe a couple of times a month in winter.  We have been fanatical about keeping it clean, inside and out, and keeping the cooking grates cleaned & well seasoned.  I even clean out the burners at least once a year, deep clean the entire grill once a year, too.  I also keep it covered.  Not one bit of rust on or in the grill, best grill we've ever had, stills looks new & cooks like new and if this one ever wears out, we'll definitely buy another Broil King.