They are called "stuff sacks" for a reason, though different people offer different opinions. Some things need to be rolled, like sleeping pads. There are certain sleeping bags of the family-camp variety that really don't lend themselves to the stuffing technique, need to be rolled, folded or sometimes both in order to squeeze things back into their impossibly small sacks.

For tents, backpacking sleeping bags, hammocks and tarps / fly's I typically employ the grab and stuff technique, gently but effectively. As far as I know, I've never damaged any gear stowing this way, at least for the duration of a trip, usually longer-term (except for sleeping bags).

I've heard / read that folding things like tarps or tents can create unnatural creases in the fabric and eventually wear out the waterproofing treatment at those points, which can lead to leaks and possibly damaging material. Others say that if you fold it a different way each time, then it's less likely to occur. I'm just wondering if this data is old or outdated (Lord knows how long ago I acquired this info) or if anyone has any opinions on this.

-Sap