What about controlling (unwanted) noise levels?
There's at least a few circuits that use 2x TL072 instead of just one TL074; and there have been attempts to glean as much out of a 4049UBE as possible by using all its inverters, but that doing so was noisy with some cross-talk within the chip.
Two inverters ▷०▷०
Tube Sound Fuzz, Red Llama, Purple Platypus, 49er, Insanity Box
Three inverters ▷०▷०▷०
Blackstone OD, Three Legged Dog, Bloody Finger
Four inverters ▷०▷०▷०▷०
Mr EQ, 22/7 (muff), Hot Tubes/Heist Wurst, Christine
Five inverters ▷०▷०▷०▷०▷०
UBE-Screamer (808), Double-D
All six inverters used ▷०▷०▷० ▷०▷०▷०
Tubesteak by Moosapotamus, Heartbreaker by ELS
(Tubesteak w/ 3inverters per bass and treble, or a 3-band Bax with 2 inverters per band.)
(Heartbreaker is a UBE screamer w/o 5th inverter for clean blend, and a Llama)
There's bunches more 4049 builds, but I don't know the number of inverters used.
I realise a bunch of inverters in the 4049 isn't the same as gain stages in a 4558 or TL07x, but the overall question remains:
How to reduce noise in IC-circuits that use all available avenues within the IC?