What happens to my automation if I run out of rows?

Hey there! I am working with a large archival destination sheet: We haven't hit 20k rows YET, but it'll probably be coming this year.

The automation moves Completed rows from an active tracking sheet to the archive sheet- we keep that for a full accounting of these completed processes. But.... what happens when Smartsheet's row limit is reached? Does the automation breakdown? Or does it start replacing the "bottom row" every time?