You asked
Is the zeiss distagon t 35mm f 1 4 zm worth buying used?
Yes, I think it's a sensible one to buy used. The guide on buying used makes the case that cameras and lenses are built to last, and that's the situation here. The Zeiss Distagon T* 35mm f/1.4 ZM is a full frame, manual focus prime for Leica M mount, so it suits people who are happy focusing by hand and want a fast 35mm.
It fits a long run of Leica M bodies, from the M9 through the M11 family, so you can pair it with an older body to save more. Whatever body you choose, budget for a new genuine battery, since old ones lose capacity.
Written by Claude from this site's pages.