First thing I do with any machine Trev, regardless of what the vendor tells me about its state, is strip the mag, test cold and HOT at all speeds, using a 'utilty factor' as a proxy for dirty plugs, carbony valves etc etc, and do whatever it needs or might think of needing. Including getting the firing interval right on K2Fs / KVFs - which is so often neglected.
It's nice to be able to do it in my own shed, I know, but if I couldn't I'd still farm the things out to people who can and who have the kit.
Nothing works for ever though, so we should be aware that 'Fit and Forget' is not a plan. Mags needs some level of maintenance, even if it's just checking the contact breaker and brushes now and again. It's amazing to me how long Lucas (and other) originals lasted with the materials of the day, to be honest - I wonder if modern rewinds will do as well. My oldest rewind is only about 15 years old, too young to tell!
I have been interested reading the hassle folk have had with short life sparking plugs of late. I don't know if it's just luck, but I rarely seem to need to replace plugs. I have a feeling we get quite good E5 98 petrol here, especially from Total - maybe that's something to do with it, I don't know. Or maybe I don't need them because I always have a spare pair about me! (It's like clutch and throttle cables, they only seem to break when you haven't got one pre-routed for a quick change . . . .)