Hey,
In my place, the roll holder has storage for about four spare rolls. Usually, my wife restocks the holder and spares, but when the roll in the holder runs out, I just take a roll from the spares and perch it on top of the roller. It's not precarious at all, it's actually quite stable. In fact, I go through the trouble of removing the empty roll and recycling it, but I won't stick the new roll in the roller, because it's way more hassle than it should be.
On the other hand, when the spares in the holder run out, I have to apply contortionism to be able to reach the cabinet where the full roll supply is, from my seated position in the toilet. I won't stand up in that particular status, unless I absolutely have to. Now, the civilized thing to do in that situation would be to restock the holder with spares again, but I must confess I almost never do that...
It occurs to me that I have no idea why I'm explaining all of this to you. It must be because I'm in between meetings here in Geneva, and I'm bored out of my skull...
Cheers,
J.