In over thirty years I have never had a Leica rangefinder adjusted, in professional and plenty of amateur use. I did always buy second hand examples that were accurate, and new cameras never needed it. They have bumped together, clattered into Nikon F's, and they just carried on working. It isn't impossible that I will need one adjusting in the future, on the basis that if it can happen it will happen, but it is a problem created in peoples minds more than in reality. And usually it is a problem created by internet forum's especially with newcomers. They are already nervous and learning a new camera, and the first advice they always seem to get is 'send you camera for a CLA' or 'set up a test chart' even before they get the hang of the rangefinder. Expectations are driven to fever pitch by comments like 'I can hand hold my Leica at 1/8 second', and 'l zone focus', or 'I always use my lens wide open'. No wonder there are so many out of focus and blurry images that worry the newcomer, but these concerns are transferred to the general ambit of Leica photography as yet more myth and things to worry about.
So if you have a Leica M use it, you may not be able to bounce it down the road like a Nikon F, but if that is the only good thing to recommend a camera you've got a more serious question to answer