Only the MP could be considered a 'camera for life' - I'm using an M2 (and a lllf) and if something breaks it can be fixed or even machined if necessary.
The M7 is a reliable camera but like my R3, if in the future something electric fails it probably isn't going to be economical to repair.
As for the M8/8.2, again fine whilst its working - is it reasonable to assume that it would still be working well in 10 or 20 years? Probably not IMHO.
You need to think more about how you prefer to work, if you are only planning on having one camera. Film, developing, printing or scanning/printing, or digital. Personally I still prefer the look of film but also use digital.
I'd buy a new MP
