For bbr, the DLPNO error is 6-7 kcal/mol for RI-MP2 calculations using def2-SVP or def2-TZVP with loose-MP2 thresholds (T CutPNO = 10 -7 ), but those errors are reduced below 2 kcal/mol for normal thresholds (T CutPNO = 10 -8 ) below 1 kcal/mol for tight-MP2 thresholds (T CutPNO = 10 -9 ). Figure compares how the number of PNOs changes as a function of threshold and basis set, comparing S66 to L7 + bbr. The DLPNO approximation eliminates more pairs for the larger systems (L7 and bbr) than it does for the smaller complexes (S66), because the number of weakly-interacting PNOs grows with system size. This remains true even as the number of PNOs grows larger in a larger basis set. That the average number of PNOs per pair is smaller for larger complexes that it is for the S66 dimers, while the DLPNO errors can still be brought to sub-kcal/mol levels with appropriately tight thresholds, suggests that basis-dependent trends observed for the S66 dimers carry over to much larger complexes, having more than 100 atoms in some cases. As such, it appears that tests using the cc-pVDZ basis set are sufficient to examine the behavior of the DLPNO error in larger complexes, for which the use of more complete basis sets is challenging if tight thresholds are used. Instead, we can use cc-pVDZ to examine the DLPNO error as a func- tion of system size and as a function of T CutPNO , with an ultimate aim being to determine whether extrapolation can be used to avoid the need for the most conservative thresholds.