Normally bearings are sealed to prevent getting too dry. I can't imagine that any of them so fast will dry out. Even with cheap Chinese quality standards.
Inside the main gear there are two
clutches. You can check
these if they can move freely and fast, by removing the seal. They must be clean and dry. Maybe a bit of thin oil is enough. With grease there is a chance on slipping.
Behind the maingear there is a
needle bearing on the shaft.
The two (or three) added
extra bearings are for extra support of the shaft on the most outer side and other side of the circlip grooves, to reduce the shaft play a bit, thereby reducing the load on the other bearings and preventing breakage of the shaft when standing on the pedals. The best is to use high quality and waterproof bearings for that.