I've seen several times that coax cable should be replaced after a few years. Why is this? Is it just because of UV exposure to the outer jacket? If so, is coax which is still on a spool good forever? Is coax used indoors subject to aging? What about MIL-STD coax, is that less susceptible to aging? A lot of questions, but the main question is, why is it recommended to replace coax periodically? Thanks de WA2EHZ