Not a landlord myself Richie Alan Naggar author of books on Life-Love-Intimacy-Purpose - however, for my client, I had suggested 5 days.

The default in our CA contract is 5 days, but I change it to 3 days( money should be wired or deposited directly to the LL account). I recently had LL who wanted check to be mailed, so we changed to up to 10 days.

Richie - Rent is always due on the first, and it is considered late if not paid by the 5th. So rent is late on the 6th, and there will be a late fee.

5 days is quite common and reasonable. please note: rent due on the first. late after ten days. ++++ this is not the tenth of the month , but rather the 11th... a very common mistake

We allow a five day grace period and after that there are late charges back to the first of the month. We will be calling and wanting to know what is going on.

That is tough Richie, a property owner has to be so careful. I would take that on an individual basis. If the person does not have a good reason and comes forward, not long.

I had someone who made the rounds and collected all of the rents.... never had a problem....

5 without penalty.  Long term renters if they call I will work with them.

We recommend 3 days.

I think most common is a 3 or 5 day grace perios and then late + late fee's on the 4th or 6th of the month. 

Two, then they get a 5 day notice, then comes the notice from the courthouse.  We have learned that the longer you delay the more they will take advantage.

But if you are firm, they will generally find a way to pay.