I had my oil and egr cooler replaced at 94,000 under warranty and immediately installed the coolant fillter to keep my new coolers from clogging again. I believe in it for sure.

 

If you don't want to install a coolant filter, then spend the money on a scangauge so you can watch the ECT/EOT spread.
It's kinda like people spending money on oil analysis - why would they do that if the engine is running fine? Because it's preventative, a small cost now to avoid a possible big cost later. All you have to do is decide what "possible" might mean, then spend (or save) accordingly. As you might have guessed, I have a coolant filter. And a scangauge.

 

Now that is thinking outside the box! That is exactly when you should install a filter. As I said before, if your 6.0 is used and does not have a coolant filter, the cooler damage is probably done. Installing a coolant filter when you change the EGR and oil coolers will help to prevent cooler issues in the future but will not eliminate them since all of the coolant does not pass through the filter. Also, if you have a filter installed and get a lot of debris that will tell you to plan accordingly for future cooler problems.

I'm one of those who installed the filter at 40K miles, changed it three times in 65k miles and have very little to no debris in the system.

A good indicator is to drain the coolant out of the expansion tank and look what is left on the bottom. If you are clean then you are probably good to go. If there is a brown or other colored residue in the bottom of the tank then you may have the start toward cooler issues. Just food for thought.

DSMMH