Time-dependent density functional theory (TD-DFT) is considered to be more efficient (in terms of its accuracy/speed ratio) than alternatives such as the approximate coupled-cluster singles and doubles (CC2), even with resolution of identity which together forms RI-CC21.
Piacenza et al. (2008)2 highlight that one drawback of TD-DFT is that "for larger conjugated systems the $\sigma\to\pi^\ast$ and $\pi\to\pi^\ast$ transitions can become significantly wrong when calculated with TD-DFT" and so for such systems RI-CC2 should be used despite its taking slower.
However, is it always the case that for small(er) systems that RI-CC2 need not be used as TD-DFT can provide sufficient accuracy, and if not what is an example where the former prevails?
 Jacquemin, D. et al. (2015). 0–0 Energies Using Hybrid Schemes: Benchmarks of TD-DFT, CIS(D), ADC(2), CC2, and BSE/GW formalisms for 80 Real-Life Compounds. J Chem Theory Comput. 11(11):5340–5359.
 Piacenza, M., Zambianchi, M., Barbarella, G. et al. (2008). Theoretical study on oligothiophene N-succinimidyl esters: size and push–pull effects. Physical Chemistry Chemical Physics. 10(35):5363-5373.