Depending on the mode, yes, you can leave your 70-pint dehumidifier running continuously. Many machines, such as the Honeywell TP70WK and the Frigidaire FFAD7033R1 have smart technology. You can set your desired humidity level and the machine will turn on or off, depending whether it is needed or not. This takes the guesswork out of trying to decide if the air has become too humid, or not. Furthermore, more advanced dehumidifiers can start working before the humidity level becomes too high, making it more efficient.