We see this as largely a personal choice, depending on the look and feel you prefer.  If left to weather naturally, the decking will turn a silver-grey colour over time, with the lovely natural grain of bamboo fibres becoming more visible (and some people prefer this look). For the optimum finish, it is recommended that bamboo x-treme decking is oiled with a high quality penetrating oil (like WOCA or Sikkens water-based oils – which come in a range of colours).  Oiling may be required every 3 years or so, depending on use, conditions etc. See the installation and care instructions for further information.