Just to be a bit clearer, I carry most of that 5L capacity empty more than 95% of the time, but I am willing to carry the extra two ounces or so of empty containers, just so I can load up on water when making a dry camp makes more sense than plopping down next to the water source.

As for the "backup insurance" aspect of having three containers, I am probably way more paranoid about water than I need to be.

Then again, Oregon's mountains are (rather surprisingly) much drier than you would think from our reputation. We have volcanic mountains, mostly, and their slopes are often very porous. Snowmelt oftentimes goes straight into the soil instead of running off as surface water.