Drinking coffee and the day you sing

I've read many times that drinking coffee the day you sing isn't good for you now my question is I usually drink coffee every morning at 6am and won't do my warm up until the evening does it still effect my voice ? 

also does singing in general the day you drink coffee do permanent damage ? 

Hi, Danny! 
It sounds like that's more than enough time for the coffee to be out of your system. The reason we sometimes warn against coffee right before singing is because it tends to be dehydrating, which can make singing more difficult. Some singers are extra sensitive to coffee, dairy, or sugar, and they avoid consuming those products before singing.

With coffee, as long as you're drinking extra water, you can help to mitigate any drying effect. If you feel good and hydrated, you're set to sing! 

Thanks so much !

Of course!