Do you tune by ear or with an electronic tuning device?
My initial training was in aural (by ear) tuning and I tuned only aurally for more than a decade. As the electronic tuning technology improved, I began experimenting with an electronic tuning device in the early 2000s. I now believe I get the best results using a mixed approach that leverages the benefits of an electronic tuning device balanced by aural tests and subjective discretion over the best musical interval sizes for a given instrument. The strength of electronic tuning devices is that they are very precise and they allow for precision even in relatively noisy environments. Their weakness is that they are dumb; they are based on algorithms rather than consideration of a particular note's relationship to the whole of a tuning. Although the electronic tuning algorithms have become quite advanced, they still are not able to account for the full complexity of achieving a balanced even-tempered tuning on the endless varieties in scaling (i.e. the mix of string lengths, diameters, and tensions) presented by piano makers. My experience is that a mixed approach exploits the advantages of technology and avoids its weaknesses, marrying the best of both the technical and the artistic.