Trailer has sat awhile, should I be scared about my tires?

The rule for me is 5 years. Once I hit that number I know that the risk goes up. I keep a spare on board and switch them out after 8 years regardless of what they look like. My tires are LTs but, the spare is an ST. They are all a year old. Tires are expensive when we don't think we need to replace them. Out on the side of a busy interstate with a blown tire and your family in the TV makes them seem very affordable.

I'm going to have that ST switched out for an LT this spring.