When exactly do you start the eviction process?

[Joe Gee]

Hello BP! 

I have a tenant who hasn't paid rent this month, and it is already the 20th!  Rent is late on the 4th, but I don't have a specified date on the lease that says "if rent is not due by XX, than eviction will begin."  I'm trying to work with my tenant.  She got behind at work and missed bunch of days, and is now playing catch up.  

It's already the 20th, should I start filing for eviction?  

In your experience, when do you start filing for eviction if your tenant is late?    

Thanks!