For production it's highly dependent on the business needs. But restarting the entire estate every day seems a big enough hit to capacity at the very least that may already be prohibitive without any further consideration.

Not to count that would require every service to be prepared to be restarted daily, which could require a more complex system than you'd need otherwise.

I'd want to restart individual components often, probably not the whole system at once.

Basically, whatever eg Google is doing.

I doubt Google restarts all their machines once a day. Obviously not all at once, otherwise they'd have massive downtime. But anyway, Google's needs are very different than just about any other company on earth (except for a handful of others like Facebook and Amazon). So, they are usually not the best example.

Yes, once a day was an example. Google uses different frequencies. However I do remember getting automated nagging messages at Google when a service hadn't been redeployed (and thus restarted) for more than two weeks.

Google as a whole might be different from other companies, yes. But smaller departments in Google aren't that different from other companies.

Getting those messages is very different (and a lot more reasonable) from forceful restarting them, which was the initial suggestion.

The restarting risk is normally so small, that there are several other things that are more important than constantly restarting to test that restart works. Continuous delivery, security patching and hardware failure will likely cause enough restarts anyway.