Yes, same here...
I always fill up the system with a 50% mix (I think they don't recommend a higher concentration than that and do state "do not use undiluted") made with distilled water.
Top any small losses up with neat antifreeze, since the alcohol part of the antifreeze does evaporate out over time, making the concentration weaker with age.
Good coolant also theoretically keeps your thermostat working for longer
though you will knacker it if you use tap water in the coolant, since scale will form on the delicate sliding part... clogging it up, even if it's not actually corroded.
Antifreeze also protects the Head Gasket. When mine burst (v6, 180,000 miles) I could see that coolant had penetrated into the gasket itself. Over time the metal mesh layers within the gasket had corroded and this had weakened the gasket. The resulting pressure one summer's day on a hot run... was too much for the remaining metal and the beast burst.
Always change the coolant... 2 years max, no matter what the pink stuff reckons...
and don't drink it or get it anywhere near your mouth (it's actually a pretty lethal neuro-toxin) and obviously now you know this, don't tip it down the drain or into the ground... take it to the old engine oil recycling place at your local tip.