What are the default settings in an EXT filesystem, after which a filesystem check is suggested automatically?

Issue

• What are the default settings in an EXT filesystem after which a filesystem check is suggested, automatically?

• Or, what does the following message mean, which is printed at the time of filesystem creation?

This filesystem will be automatically checked every 38 mounts or 180 days, whichever comes first.  Use tune2fs -c or -i to override.