I think we are missing the point here , each job you go to price has to be judged on its own merits .As we all know (hopefully), plastering is all about preparation and when looking at re'skimming walls i always make sure to have a good tap around to see if there is any loose plaster that may need to be removed . If the old wooden staff beads are not in a good condition then they should be taken of as well but if you are having to patch the walls in the first place why not remove them anyway . There is nothing worse than having to go back to a re'skim because it has cracked after decoration .YOU can do the best finish in the world but if if cracks because of the poor prep then its only down to one person . Its you name and rep at the end of the day.