I believe that the way old recommendation was 3 years for a coolant change. Back in the days of copper/brass radiators and iron engine blocks and cylinder heads. I stuck with that and only rarely had any cooling or radiator troubles. Good old green Prestone usually. When engines with aluminum heads on iron blocks and often aluminum radiators became more common in the 80's/90's, there was a lot of noise about going no more than 2 years due to the dissimilar metals situation along with the coolants of the time. I for one, believed that. My Dad did not and had way more water pump failures than anyone. As many cars still have that iron/aluminum mix, they must have improved the coolant chemistry since then.
I've only replaced one oem aluminum, plastic tank radiator ever and that was on a Nissan Altima that was about 14 years old at the time. The replacement aftermarket Al. rad lasted 2 years. I recently replaced the rad in my '82 Dodge truck. I lucked into finding an old new aftermarket replacement in a box that was actually also a copper type. Even aluminum 22 in. core slant 6 radiators are very scarce, as the big aftermarket names dropped the application. The 39 year old factory copper radiator evidently lasted that long though it likely may have recored at some time. There used to be a couple top notch rad shops around here, but all gone as a dead industry.
I'm going with a 10 year max idea on my two Scions that have the SLL pink Toyota/Aisin coolant. I do believe it's good for the long haul, but not magic. They're at 7 and 8 years age now. Unless I decide to change hoses prior to that time. Toy claims lifetime for it, like their lifetime WS ATF. I have heard claims that the lifetime moniker has something to do with advance fees/credits for eventual chemical recycling needs in Japan, if they stated a replacement interval.