Validity of 17025 accreditation

You asked Once a lab is accredited to 17025, does this expire?

ISO 17025 accreditation is awarded for a cycle which could vary between two and five years, depending on the discipline and accreditation body’s policies. Before the end of the cycle, the laboratory needs to reapply for accreditation so that a new certificate will be issued before expiry. At this point the assessment will be as if as per original application,  in other words more thorough.

You also asked are there defined time frames for external audits, eg ever other year or so?

Yes these are called surveillance assessments. The frequency depends on the accreditation body, but are typically annual. I suggest you engage with the accreditation body to obtain specific information for your laboratory.

For more information have a look at the Webinar What are the steps in the ISO 17025 accreditation process? [free webinar on demand] at https://advisera.com/17025academy/webinar/what-are-the-steps-in-the-iso-17025-accreditation-process-free-webinar-on-demand/ or attend the next scheduled webinar on that topic.