Accounting has the quietest great economics in professional services: a business client retained this year is very likely retained next year, and the year after. Individual tax returns bill $200 to $600 once a year; business clients on monthly bookkeeping-plus-tax arrangements run $500 to $2,500 a month and stay for years. Those two markets share a benchmark band and almost nothing else.
The retention math is the entire argument for paid leads in this vertical. A $1,000-a-month business client at 60% margin produces $7,200 of kept profit per year, and multi-year retention is the norm rather than the exception. Even modest close rates support lead prices that look reckless against a single tax return, which is why firms advertising for business clients outbid firms advertising for 1040s without breaking their math.
Seasonality is sharper here than anywhere outside the trades: January through April floods the market with tax-return demand at peak lead prices, while the business-client pipeline runs year-round with far less competition. Firms that advertise for business relationships in the off-season and let tax season fill itself buy their best clients at the year's cheapest prices.
Worked example
A worked example: a firm signing business clients averaging $12,000 in first-year fees at 60% margin keeps $7,200 per client. Closing 20% of qualified inquiries makes a lead worth $1,440; even the conservative divide-by-three ceiling is $480, several multiples above the market's expensive end. On individual-return math ($400 return, same margin, 30% close), the ceiling is $24, below the band's cheap edge: the same firm, two different businesses.
The capacity caveat particular to accounting: the constraint is senior review hours in March, not lead flow in October. Signing clients the practice cannot serve at quality during peak season churns them by summer, so lead budgets here should follow hiring plans, not precede them.