Should I rewrite my capability statement for every sources sought, or is one version enough?

You should tailor your capability statement for every sources sought notice. The contracting officer is looking for specific capabilities and experience that align with the notice, and a generic document will not highlight your firm's strengths for that particular requirement. For federal solicitations, the contracting officer will review your response to determine if your firm is a responsible prospective contractor and if there is a reasonable expectation of offers from two or more small businesses, as described in FAR 19.502-2(a) for acquisitions below the simplified acquisition threshold and FAR 19.502-2(b) for those above it. Update the NAICS code, your past performance examples, and your differentiators to directly address the requirements in the sources sought. The length should be concise, typically one or two pages, focusing on relevant information. Both the capability statement and the narrative response are read by the contracting officer to assess your firm's suitability for the work.