The validity period certificates were 2 years on vCenter Server 6.5 Update 2 or later, however, when you renew or replace certificates through Web Browser (accessing to https://vc_ip_or_hostname/psc), validity period will be 10 years.
The validity period of all certificates issued by the VMware Certificate Authority (VMCA) is reduced to 2 years
The default validity period of the certificates issued by VMCA was 10 years. According to the CA/Browser Forum recommendations, certificates issued after March 1, 2018 must have a validity period no greater than 825 days or 2 years.