Before changing field, what matters most is whether you have done any of the new work yet, how much of a pay cut you can absorb, and whether anyone in the new field knows you. The most common mistakes are treating a certificate as evidence when employers read real work very differently, postponing the switch indefinitely behind one more course, and underestimating that a thirty per cent pay cut takes roughly three to four years of ordinary raises to recover. Most successful switches happen sideways inside a company rather than by applying cold.