My first post, and I'm looking for some advice! We're having engineered wood put in a bedroom (light oak), and throughout the ground floor (dark), and are not sure what top layer wood thickness to go for. I think we've settled on 4mm for the bedroom, but I'm wondering whether we should pay pay the extra for 6mm for the ground floor, as this will take more of a beating, and may need to be sanded and resealed in the future. This is our forever house, so I'm hoping to get many years out of them!