Depent of your speed, i made some calculations based on the speed, the time is for scan all the range in that bit space:
Puzzle 120 @ 1 Petakeys/s : 21074771622667 years
Puzzle 120 @ 1 Exakeys/s : 21074771622 years
Puzzle 120 @ 1 Zettakeys/s : 21074771 years
Puzzle 120 @ 1 Yottakeys/s : 21074 years
Puzzle 160 @ 1 Terakeys/s : 23171956451847141650870193314 years
Puzzle 160 @ 1 Petakeys/s : 23171956451847141650870193 years
Puzzle 160 @ 1 Exakeys/s : 23171956451847141650870 years
Puzzle 160 @ 1 Zettakeys/s : 23171956451847141650 years
Puzzle 160 @ 1 Yottakeys/s : 23171956451847141 years
Puzzle 256 @ 1 Terakeys/s : 1835871531540401373407708412745559168131740612197318060720 years
Puzzle 256 @ 1 Petakeys/s : 1835871531540401373407708412745559168131740612197318060 years
Puzzle 256 @ 1 Exakeys/s : 1835871531540401373407708412745559168131740612197318 years
Puzzle 256 @ 1 Zettakeys/s : 1835871531540401373407708412745559168131740612197 years
Puzzle 256 @ 1 Yottakeys/s : 1835871531540401373407708412745559168131740612 years
I know there is no puzzle 256, but that is the exact time for the real wallets.
With Pollard / Rho we calculate:
Puzzle 120 @ 1 Yottakeys/s : < 1 sec
Puzzle 160 @ 1 Terakeys/s : ~ 27107 years
Puzzle 160 @ 1 Yottakeys/s : < 1 sec
Puzzle 256 @ 1 Yottakeys/s : 10790283 years (real addresses)
We can see here, how important a high keyrate is.
How much is 1 Yottakeys/s for (Pollard / Rho) ?