I use one camera, an M2, and one lens, a 50mm. I have some other cameras, but they now serve as seldom-used backups if the M2 is in for repairs/CLA. The last time I used a 35mm lens was about five years ago.
There is nothing restrictive or ‘disciplined’ about any of this, as it just fits my style. When I first started shooting film (after switching from digital), I rotated among three or four cameras, finding myself gravitating more and more to the Leica iiif. The M2 followed a few years later.
Ultimately would rather not think about which camera to choose; perhaps I get to compulsive about it, like I did with zoom lenses.
Anyway, it really was just a natural process of elimination based largely on ergonomics (as all my other cameras were equally capable).
Likewise, a normal lens best suits my view; not necessarily averse to a wide, but the 50mm is versatile enough, and I never feel the need for anything longer.
Things might change down the road, but a rangefinder, Tri-X, and a 50mm is all I need now.