Three-dimensional laser nanoprinting represents a unique approach for implementing on-chip hollow-core waveguides. Here we discuss the fabrication characteristics of the light cage geometry arising from the used two-photon polymerization lithography. We reveal the current limits of achievable waveguide length (3 cm), single strand aspect ratio (8200) and modal attenuation. Very high reproducibility for light cages on the same chip is found, while different conditions in fabrication cycles impose chip-to-chip variations. We also highlight the relevance of including reinforcement rings to prevent structural collapse. The results presented uncover key issues that result from nanoprinting light cages and can be transferred to other nanoprinted waveguides.