Antifreeze/Coolant Change Intervals

[danachevroletfor1967]

I have a question for you guys that I'm sure have more experience than me related to car things. I have a 1978 K5 Blazer that I had the antifreeze/coolant changed in 2022 with Prestone's longer engine life coolant (10 year or 300,000 mile guarantee). Now I know I'm never going to approach 300,000 miles. My question is do you think this antifreeze/coolant would be alright to leave in for say 5 years? I've often heard that the anti freezing and anti boil over properties last for decades. It's what is added that wears out over time or mileage, such as anti-corrosives and lubricants that require the frequent changes. My owner's manual says to change the antifreeze/coolant every 2 years, but I'm sure today's are much improved over 47 years ago. I drive the Blazer no more than 500 miles a year.

What do you guys think? Any advice appreciated.