Didn't they both do well to have such long careers, down to being built with good materials and good maintenance bearing in mind that most of their working lives things like Boiler water treatment and the more modern filtration in the Hotwell were not available, the filtration in the Hotwell would be something like Coir or Coke ( not the Colombian marching powder
) along with regular Salinity Testing of the Boiler(s) which was carried out by taking a sample of Boiler Water from a Sample Cock (rather than a Valve) at the back of the Boiler(s) into a tall metal jug type Container dropping the Stainless Steel tester in which looked like a Fishing Float and taking the reading, all this was done whilst wearing thick Asbestos Gloves and the concern particularly on the older vessels that if the Sample Cock on the Boiler snaps off you are in deep doo-da as you are stood in the limited space between Boiler and usually a Bulkhead depending on the Ship design, although admittedly not as bad as crawling into an hot empty Firebox whilst the Boiler is on reduced pressure to plug off a leaking Firetube
No wonder I was thin in the days of Steam.