When should I file eviction?

[Jenny Scott]

I got a bad renter and I want him out.

My story is, at the beginning of this month, I rent my property to a guy. We signed the lease(1 year). He gave me the rent for this month but did not have enough for security deposit. I believed him when he promised to deposit security deposit to my bank account the next day and I gave him the key before I saw deposit. However two weeks later still no security deposit. Even worse than that, he now completely ignores my calls and wants to live there for free.

I sent certified mail out to state:
1. not paying security deposit is a serious default and informed him the lease has been cancelled.
2. demand my property back and ask this guy to move out by the end of this month, otherwise eviction.

Now, it is only about a week to the end of this month. I am thinking what should I do next? If this guy does not leave:
1. Is it fine to demand the property based on "consider not paying security deposit as a default." In lease, it has something like "If defaults which includes but not limited to not paying rent, landlord can terminate the lease and give tenant at least 1 day to move out." (BTW, this is in Georgia)

2. What is the best reason and when is the best time to file eviction? I know most of them are "not paying rent". But I want to end the lase and want him out. I am pretty sure this guy is not going to pay rent for next month. Or should I better to wait several more days until Jan 1 past then file for not paying rent? (That will assume the lease is still valid even I already told him I already cancelled it.)

Thanks
Jenny