answer 1
HEPA filters are not washable. For maximum performance, it is reccomended that you replace them, on average, every 6 months. This will depend on the dust and dander in your home, as well as if you are an allergy sufferer. The purpose of the filter is to clean the air expelled from the vacuum during your cleaning; essentially putting clean air back into the room. The more frequently you replace them, the better the air emissions from the vacuum. I am an allergy sufferer, with one cat. I find it best to replace every 3 months. They are relatively inexpensive. Overall this vacuum has low costly maintainence. The remaining parts are completely washable and reusable.
answer 2
i just called bissells 800 number and ask them if that filter on the side is washable and she told me no, but i scrolled down to parts and all and it was like i believe around 13.00 to replace, how long it last she couldnt tell me, i was wondering too, been thinking about getting this