You can use the suction device as many times as you need to so that the mucus or snot is cleared from the babies nose.
Usually though using the suction device once or twice per day is enough to keep the babies nose clean and free of snot and mucus.
However it's recommended to not use any suction on your babies nose more than 3 times per day as it can cause irritation to your babies nasal passages and you might do more harm than good.
You can also use some baby safe nasal sprays or use some steam in the babies room such as through a vaporizer or humidifier to add moisture to the babies nasal passages.
The insides of a babies nose is more delicate than an adults so you need to be more careful.