For WHOLE grains (or dry beans) they work well. Small types of pasta, too. But while they are sturdier and less permeable than many plastics, they aren't IMpermeable... that's why soda goes flat in them over time. So, anything that has the potential to turn rancid in storage (rolled oats, grits... almost anything that isn't in it's original "as harvested" form) will likely start getting funky within 2-3 years (max).
And, of course, the temperature where you are storing them is important... for every 10 degrees over 70 degrees, storage life is halved... for every 10 degrees below 70, it doubles.
However, they are pretty much insect and rodent proof... even rats find it nearly impossible to chew through them, mostly due to their shape and lack of "edges".
Summerthyme