Run your tests more often

There's no value in a test suite that isn't run and the less often it's run, the less likely you are to spot a failure or regression.

If the tests are only run weekly, you aren't going to be aware of an issue that could have been introduced at the start of the week until the tests are run.

Then, there are more changes that need to be reviewed to find the cause of the issue compared to if it was found sooner.

Ideally, everyone should be running tests locally as well as having them run automatically in a CI pipeline for each commit.

As soon as a failing commit is pushed, it will be identified and it will be easy to fix or revert.

Also, the more often you push changes and in smaller batches - the easier it will be to diagnose and resolve the issue.