For those using the ATLAS web service, your updates will happen automatically in real time.
If you're a batch distributor, it's a good idea to update your content daily. With 150-300 product listings getting updated every day, this ensures your customers always see the most relevant content.
To make this easier, you can use the DELTA_DATE parameter to pull only the recently updated and new products since your last update. This way, you keep everything fresh and up-to-date without any hassle.