Definition
A lead that has been engaged by sales and confirmed as a fit for pursuing a deal. Further along the funnel than an MQL; typically has confirmed budget, authority, need, and timeline.
Why it matters
An SQL matters because it marks the point where a business commits real selling effort — proposals, calls, custom quotes — to a prospect, so being disciplined about what qualifies protects the most expensive part of the process. For an owner doing their own selling, treating a warm-but-unready lead as an SQL is how hours get sunk into deals that were never going to close. The value is in the honest gut check on budget, authority, need, and timing before pouring in the work.