Closed and expired federal solicitations, retained because they are the best available record of what an agency actually bought and how it described the requirement. Archived notices are the raw material for capture planning: they show which offices buy your NAICS code, how often a requirement recurs, what set-aside the contracting officer chose last time, and what the statement of work asked for before the recompete. Reading the previous solicitation is usually the fastest way to understand an incumbent's scope and to judge whether a follow-on is worth pursuing. Filter by agency, NAICS, set-aside type or posted-date range to reconstruct a buying history, then cross-reference the resulting award to see who won, at what value, and when the period of performance ends. Requirements that recur on a predictable cycle are the ones worth staffing a capture effort against well before the next notice posts.