Run the two-question test: Does the site load fast and look credible on a phone? Can a stranger tell what you do, where, and how to contact you within five seconds? Pass both, and your money is almost certainly better spent on traffic and follow-up than on a rebuild.
Rebuilds are the most over-prescribed remedy in small-business marketing — often proposed because they're a big invoice, not because they move leads. A mediocre-looking site that converts beats a beautiful one nobody visits.
The exceptions where rebuilding genuinely comes first: broken mobile experience, multi-second load times that resist optimization, or a platform you don't control (see: marketing you own). Otherwise: traffic, tracking, and follow-up before pixels.