Work backward from your real unit economics to find out exactly what you can afford to spend on paid ads.
The average revenue per completed job. If most jobs are $8,000–$12,000, your AOV might be $10,000.
The % left after direct costs (labor + materials). A $10k job with $7k costs = 30%.
The % of gross margin you'll spend to acquire a customer through ads. A common starting point is 20%.
The % of estimates that become customers. 1 in 4 closed = 25%.
Your current annual revenue.
The annual revenue you want to reach.