0 cycles is absolutely ok.
a full backup won't age until all dependent incr. or diff. or log backups age.
so if you follow a policy of weekly full on sun with your 3 day retention, the last weeks backups (full + 6 incr.) will age on wednesday, due to the last incr. of last weeks saturday to be available for 3 days.
If you use cycles, your last backup will be kept forever, unless you delete it or override the cycle rules for decommisioned clients