Not every bounce means the same thing, so they are not treated the same.
A hard bounce:
The address does not exist, or the domain does not exist. There is no point trying again, so the address is blocked from future sends immediately and added to your suppression list.
A soft bounce:
Something temporary went wrong. The mailbox was full, the server was busy, or the message was greylisted. These usually fix themselves, so a soft bounce does not block the address. It is recorded and nothing else happens.
When a soft bounce becomes a block:
If an address soft bounces five times within ninety days it is treated as gone and blocked, with the reason recorded. Older bounces outside that window no longer count, so an address that had a bad week last year does not start out part way to being blocked.
If the bounce cannot be classified either way, it is treated as soft. Being cautious keeps real people on your list.
Every bounce of either kind is logged with its reason and which provider reported it, so you always have the full history.
Getting bounces reported to you:
Your sending provider reports these through its webhook. On the Sending tab each provider shows its own webhook URL with a copy button. Paste it into your provider settings and enable the bounce, spam and unsubscribe events.