HSReplay.net receives and processes millions of replays each day. The vast majority of replays are never viewed, and as such we eventually will delete replays to limit the storage required for replays.
While the information may vary in future, we will give sufficient notice on your replays page or other suitable places to ensure you don't unexpectedly lose a replay..
Currently, replays will be automatically deleted no earlier than 6 months after the game was played. However, if you view a replay, it will currently not be deleted.
In order to keep a replay you can visit the replay page, which will count as a view.
Regardless of these rules, you can manually delete a replay you uploaded at any time by logging into your account, opening up the page of the replay and clicking the "Delete" button in the bottom left corner.