See alltheplaces.xyz for continuously updated straight-from-the-primary-source opening hours of chains of shops and restaurants, public facilities such as libraries, etc. This is probably as accurate as it gets AND you have the confidence of knowing exactly where the data came from (down to the URL) and when it was last checked.

Some OSM contributors go brand-by-brand/operator-by-operator in making sure OSM features have the most up-to-date opening hours added to them from matched ATP features. As such, OSM may be fairly accurate for chains too.

For a standalone shop or restaurant the opening hours situation is usually still better with Google Maps rather than OSM. There aren't enough OSM contributors who care enough to check and maintain opening hours for every shop, restaurant, fuel station, etc.

Both this and addresses is something that's really easy to survey with StreetComplete.

Google has the benefit of having their own street-level imagery for house numbers and street names, Android devices for real-time traffic info, and the ability to simply scrape web pages for shop data including opening hours. but in places with a reasonable number of active mappers, OSM is so much richer and more up to date.

Agree, which is why I added support for displaying when the hours were last updated in CoMaps

Organic Maps didn’t accept my PR with it…

https://codeberg.org/comaps/comaps/issues/688

IME there is no reliable source: Stores' (including restaurants') own websites are inaccurate enough that I need to call them if I need to be sure. Yelp, etc. are at least equally inaccurate.

I'm sure it annoys the stores that keep their website and Yelp etc. updated but there is no way to know who is reliable.