Radiator / cooling system servicing (flush or just drain & fill?)

I didn't see many recent search results for this. I'm curious as to what others are doing as far as servicing their coolant and cooling systems. I understand the Toyota long life coolant is good for 10 years. From my searching, I see mixed thoughts on just draining and filling the coolant, flushing with chemical radiator cleaners, and flushing with just distilled water. How does one assess for the need to flush (how to identify scale build up, rust, etc)? Also, does anyone replace their thermostat and gasket at this point just because it's cheap to do so, or do you wait until it fails to replace?
Thanks,
Josh

 

You'll probably get several different answers, but I always do the complete back flush

IMO, your 2009 should not be full of junk that will back wash into the radiator and do any damage.

My thought is ... if you always back flush, you should never get a build up of crud. I've seen some pretty nasty crap that's left in there over the years when people only do drain and fill, so I understand the concept.

Might be a good time to go ahead and replace the thermostat, if you haven't done so in a while ... its what ? 10 bucks ?
Good time to do it, I would think