In general, yes. Assuming the chemistry and system is the same type - always worth testing this again for the larger system but this should make it quicker. I noticed a very slight increase in the cut-off requirements going to large systems in the past, but it was tiny.

I agree with Victor's answer. I'll add one extra condition, and that is that the smaller system should be representative of the bigger one, i.e. different in size but somewhat similar to what the bigger system contains. For example, with the FeCr alloys I work on the plane wave cut-off from a 54-atom 2x2x2 bcc cells supercell is very well transferable to a 250-atom 5x5x5 bcc cells supercell. But if the smaller system contained only a FeCr dimer and otherwise was completely empty, then the plane wave cut-off would not be transferable to the large system. Because a dimer in otherwise empty space is much harder to describe with plane waves than a nicely periodic system of atoms. So the FeCr dimer would require a much higher plane wave cut-off.

You can save yourself time by determining the plane wave cut-off in a smaller system, but make sure that your smaller system is 'kind of the same' sort of system as your large one.

Tanks by the answers! Then, it being possible to determine the plain wave energy cutoff via a smaller representative system, is it also possible to determine other DFT properties like smearing, charge density cutoff using such a representative system?

Tks

I think the finite temperature smearing width is transferable between similar kinds of systems of different size. I wouldn't know about charge density cutoff.