Raman increases OSNR without much penalty to allow longer reach (skipping Regens) and/or longer spans (or skipped sites) for all fiber types and links. Modular Raman implementation allows customized designs. Higher power Raman modules may be needed for high Aeff fiber types. Raman cost should be viewed at both beginning & end of life.
Raman works on aged fiber and through multiple connectors as long as simple installation cleaning is performed (high power connectors recommended for > 10 dB Raman gain). Raman helps deal with varying span losses during operation. Raman and EDFAs should be designed to work together. Raman has been commercially deployed for > 10 years. Operating anetwork with Raman should not be more complex & should add robustness!