As is in Shri Sai Satcharita, by Hemadpant .. Chapter VIII Page 46

Om Sai Shri Sai Jaya Jaya Sai

Ultimately when their merits and demerits both drop down (are got rid of) completely, they get their deliverance and become free.  To put the matter in a nutshell, souls get their births or transmigrations according to their deeds and intelligence (development of their minds).

Bow to Shri Sai - Peace be to all