Demigod how long till full buff

[Dracon]

So, I started playing around wiht a demigod character, and know that it's better not to convert from the beginning, as they will recieve a buff over time, that is meant to stay. But how long does one have to remain without a deity to get the full bonus?

[Cain]

depends on faith and favour so depends on your ability to prey and the sacrifices you make to alters