Yeah, two-ply becomes four-ply or even six-ply. Toilet paper is cheap, so why not? Unless you like pulling up your pants and buckling your belt without using your index finger...
An old guy I used to work with was in the army in the 50s. He said he was instructed by the DI to use a single square of toilet paper....
You quad fold the sheet, then tear off the corner, and save it.
Unfold the sheet, and the corner you tore off left a hole in the middle.
Put your finger through that hole.
Use your finger to wipe your ass, then wipe up with the toilet paper to clean your finger when done.
That corner you saved? That's to clean under your fingernail.
:^P