Let me illustrate:
1: Submit the first lease and wait 1440 blocks.
2: Once lease is active, submit a new one which becomes pending (do with at least 1440 block left in active to avoid any inactive balance)
-- note: if a new lease is issued before the pending becomes active, the pending is overwritten with the new.
3: When the active lease expires, the pending becomes the new active.
4: Repeat from 2.