After the drum end soon message appeared on my 4070CDW printer, I waited 'til printing got really bad and ordered a new Brother brand drum. Installing was simple and I was back in business with good printing again. Then I noticed the drum end soon message was back, although printing was/is fine. I will remove the cartridges from the drum and then the drum itself. Assuming I don't see something obvious I will reinstall. If the message is still there I will need to talk with Customer Service.
I c an neither recommend or not recommend at this time and will leave the next question blank...for now.