This is in general for any car. What are the benefits of doing this?

Depends on the antifreeze. Two years for the old style green, 4 years on dex and newer antifreezes like the 5/100 stuff out now; I don't like to leave that stuff in there as long as they claim it will last.

I don't flush mine; I just drain and fill every 6 months. I figure if I do it often enough, I won't have to ever flush it. So far it seems to be working, because it'* clean and keeping the engine cool.

Oh and I forgot to mention - I clean out the overflow bottle at the same time, so that it always looks white.

Here'* a shot of my overflow bottle; I like to keep in clean.

If you're doing a drain n' fill (with a 50/50 mix) every 6 months than I'm SURE your system is more than fine. My personal favorite was to hook up one of those Reverse Flush Kits every other or every other other year with Regualr Coolant. With The Vibe, there'* a small controversy as to which coolant they put in it. The owners manual says Dex-Cool but most others are saying use the Toyota Coolant. When the time comes I might just go with the Prestone Extended Life that'* compatible with all coolants.

I normally flush mine before every other summer