How do you decide if a career switch is realistic?

CareerFitMap is launching today, and the core question behind it is simple: before rewriting a resume, how can someone tell whether a target role is a realistic next move?

I am especially interested in cases where someone has transferable experience, but the evidence is scattered across past roles. The current approach compares three inputs: the resume, the target job, and optional personality / communication-style context, then turns the gaps into bridge paths and a 90-day plan.

If you have switched roles, hired career switchers, or coached candidates, what signals do you look for before deciding the gap is bridgeable?