I can guess that he probably is a painter and supports himself by selling his paintings or he is some kind of cleaner (chimney sweep?) based on the cleaning supplies behind him.
Based on the objects in the room I would guess 50-60 years, based on the clothes I would guess 40-50 years. So maybe 50 years?
Just looking at the room it looks like a storage room, but considering that there is furniture it's probably a living room.
