In user testing, we found that the original default of 100 results per page made the site appear slow, especially on mobile or low-bandwidth devices. For launch, we reduced the number of results per page to 20.
We've received feedback that 20 is too few.
Ultimately, it may be ideal to have an infinite-scrolling UI with lazy-loading. In lieu of that, add an additional toggle to allow users to set results-per-page themselves.
lizadaly
commented
7 years ago 
In user testing, we found that the original default of 100 results per page made the site appear slow, especially on mobile or low-bandwidth devices. For launch, we reduced the number of results per page to 20.
We've received feedback that 20 is too few.
Ultimately, it may be ideal to have an infinite-scrolling UI with lazy-loading. In lieu of that, add an additional toggle to allow users to set results-per-page themselves.