As mentioned by Dave and others,know the layout of the property and use already fixed voids and conduits as much as you can. If you THINK the plaster is bad in an area,bank on that all falling off...a few years ago,i assisted a pal on a lived in rewire and he spent an hour skillfully chasing a 4" path floor to ceiling on landing in the middle of the 2 foot gap between bedrooms. Dead pleased he was,but as he tacked the capping over all the cables,the jolly lot,both sides came down. Think of that dust cloud when the twin towers came down,and we enjoyed gritty tea and biscuits as we hoovered...