How to update product information page frequently?

Hi,

Based on online guide, Google likes fresh contents. So it is better to update the contents frequently.

However, for a product information page, most of the contents will not change frequently, as below:

1. Introduction of the product.
2. Main features of the product.
3. FAQs of the product.
4. Testimonials of the product.
5. Screenshots of the product.
6. Guide of the product.
7. Case studies of the product.
8. Related products.

None of the above will change every day. Also it is unlikely to upgrade the product version every day or every week.

So:

1. How can make the product information page updated frequently?
2. How many contents should be updated(for example, 20% or 50%) so that to make Google think it is fresh?

Thank you.