Summary: Save scroll position when users are likely to compare content in a long static list.
One of the fastest ways to frustrate a user is by losing their progress. Imagine this: you scroll, scroll, scroll down a long list…click…read, and hit the Back button, only to land back at the top of the list instead of where you left off.
It’s a small moment, but failing to save scroll position increases the interaction cost of using sites with long pages. Most of the time, saving scroll position reduces user effort.
That being said, there’s no always in UX. It is important to consider user intent, and there are a few cases where saving scroll position is not the right choice.