On FilePaste, you pick the TTL before upload. The current options are 1 hour, 1 day, 7 days, and 30 days. That choice becomes part of the share metadata.
Why expiry helps
Expiry is useful when the content is temporary by nature: debug output, screenshots, one-off exports, or quick notes between devices.
What expiry does not mean
Expiry does not turn the service into a secure vault. It simply limits how long the link is intended to stay active.
How to choose the TTL
Pick the shortest window that still gives the recipient enough time. Fast support exchange might only need an hour. A handoff across time zones might need a day or a week.
Try it from the homepage tool, or use temporary file upload if the share is clearly short-lived.