I bought my house in 2010 and painted the 22.5 sqm of jarrah hardboard (I think) decking around 2018 using Cabot's Deck and Exterior Stain. I did not sand back then. Currently, some of the boards need replacement due to wear and tear.

ear and the stain is wearing thin.
Questions- should the whole decking be sanded first before this next paint? I have some of the original Cabot's stain left, is it OK to use? Pls see pics Thank you - I would appreciate your advice

