The phrase "continuous usage" means using something without stopping or taking breaks. It means using or doing something consistently and without interruption.
Sentences with «continuous usage»
A single full charge of the battery will be enough to support 24 hours of continuous usage of the e-reader. (goodereader.com)
It adds glow to the skin with continuous usage over a period of time. (planetbeauties.com)
Plus, its keyboard doubles as an extra battery pack, so you'll get at least 15 hours of continuous usage on it. (techdomino.com)