Yes the metal internal parts rust.  But simply coating with spray on oil like WD40 or spray lithium grease will give more years of service.  Spray the hinges and latch mechanism every 3 months or so helps a lot. 
But Lifetime should really make a design with stainless steel for the internal parts, that would solve many problems.
  Also cover the composter during rain to keep your mix from getting too wet.  I got 2 giant plastic bags and simply drop a bag over each bin.