How long does it take for you to go through a 4L can?

Just asking in case a 2-3 month period from opening would have meant the oil has oxidised, gone stale or whatever. I'd rather use a recyclable steel container rather than four or eight plastic bottles, which most likely would go to landfill if not recycled by our council's recycling contractor.

If locally-made oil was available at a competitive price and in a 4L can I'd buy it. ^