Ask a founder what a bad sales hire costs, and most will say the salary. A year of pay, gone. Maybe a signing bonus. Maybe relocation.

That is the smallest number in the equation.

The real cost shows up in the eighteen months around that salary — the ramp time nobody accounted for, the pipeline that never got built, the deals that went quiet because follow-up slipped, and the four to six months it takes to find and onboard whoever comes next. Add it up honestly, and a failed sales hire at a professional services firm runs $200,000 to $500,000 once you count everything, not just the paycheck.

And the odds are not in your favor. Industry research puts sales-hire failure as high as 60% within eighteen months, once you count reps who miss quota, leave voluntarily, get managed out, or simply underperform and linger on payroll. Sales turnover runs near 35% — about three times the average across other roles. Most sobering of all: 89% of hiring failures trace back to fit and attitude, not a lack of skill. That means a sharper interview process will not fix what is actually broken.