Use one page. Use two pages. Include every relevant keyword. Let the experience speak for itself. Résumé advice sounds definitive until you ask which job, employer, or reader it’s for.
What fits on the page
Titles, dates, tools, and outcomes are easy to list. Decisions and constraints take more room. “Led a migration” might describe someone who planned the cutover, someone who ran it, or someone who coordinated the teams. The short version leaves all three possibilities open.
What matters for this job
For a role that owns production changes, the strongest evidence might be a decision about whether to proceed and how the applicant checked the result. For a role that coordinates across teams, planning handoffs and keeping people informed might matter more.
What First Read should help with
Start with what the employer needs. Show which parts of the résumé support each requirement and where the match is unclear. Applicants can use the same comparison to decide which parts of their work to explain more clearly.