A million cycles or 6 monthsof test time can be considered as...

A million cycles or 6 months
of test time can be considered as the maximum limit for
duration of the experiments operating at near to maximum
ratings. Devices that do not fail/degrade after 6 months of high
temperature power cycling testing are considered robust, and a
more severe operating condition is required to accelerate
failure.
https://www.osti.gov/pages/servlets/purl/1325461

"The data retention test was conducted in CEA/Leti testing facilities by Weebit Nano engineers under
various testing conditions, including elevated temperatures for various periods of time to accelerate
ageing of the devices in order to replicate 10 years’ operation in the field. Results showed that
Weebit’s ReRAM SiOx arrays did not present any significant degradation with information being
detected with no corruption after 10 years’ field operation."

https://weebit-nano.com/wp-content/uploads/2019/03/Q2FY19-Activities-Update.pdf

Unlike most other ReRAM technologies, Weebit Nano has focused on using Silicon Oxide as their phase-changing material. Their memory cells consist of metal contacts (Titanium), on either side of their phase-changing structure. Their technology allows for up to 1 million read / write cycles and has demonstrated a working 1Mbit device using 40nm technology.

https://www.electropages.com/blog/2021/05/weebitnano-patent-and-what-reram