A Certificate of Good Standing is a point-in-time confirmation. The state is attesting that, as of the issue date, your entity is properly registered and current on its filings. There is no expiration date printed on the document, because the state cannot promise you will stay in good standing tomorrow.
What actually matters is the recency requirement of whoever asked for it. That is the number you need to satisfy.
Recency windows by requesting party
Banks and SBA lenders: typically within 30 days of loan closing. SBA 7(a) and 504 underwriting codifies the 30-day window.
Commercial landlords: typically within 30 days of lease execution. National retail landlords often enforce strict 30-day recency.
Foreign qualification (registering in a second state): typically 30 to 90 days, set by the receiving state. California, New York, and Texas commonly require within 30 days.
Government procurement (SAM.gov, GSA, state portals): typically 30 to 90 days, re-verified at major milestones.
M&A and capital markets: within 30 days for diligence, and a fresh bring-down certificate within about 5 business days of closing.
What to do if your certificate goes stale
If your closing or filing date slips and your certificate ages out of the required window, just order a new one. Most states issue within 1 to 2 business days, and several deliver same-day. There is no penalty for ordering a fresh certificate; it is the standard practice when timelines move.