I hear ya re: budget.
Last fall I got around to flushing/changing the coolant in my '94 F150. The FACTORY coolant.
I'm sure many would howl at the callousness of my abuse; however, it's the only vehicle I've ever bought new, and I've taken care of it from day one. Over the years I have checked the coolant, for color and with the hydrometer. Like other things on the truck, I finally changed it out of pure guilt. Like the air filter element I changed at 80,000 miles and over 10 years old- changed out of pure guilt because really, it wasn't filthy and could have stayed in service. This is the truck that still proudly wears the factory battery!
In MN!
Oh, and when I did the coolant flush, there was no evidence whatsoever of any cooling system problems. There was a wee bit of sediment in the overflow tank. A visual down the radiator neck showed no accumilation of anything. Oh yes, in addition to the 16 year old battery, it proudly wears all the original hoses and plug wires. Shoot, I have replaced the serpentine belt once though.