You should. Without regular cleaning you put your health at risk.
Dirty portable room humidifier can release bacteria from standing water into the air causing flu-like symptoms.
How to clean portable humidifier: Drain, rinse and dry every day. Every week wash with vinegar, disinfect with a bleach solution, rinse thoroughly. – Consumer Reports.
Consider a whole home humidifier for hands free comfort and better health. Learn more about whole home humidifier.