I've found SRS (with Supermemo) is indispensable for learning vocabulary of languages in which immersion is not possible or too impractical e.g. ancient Greek/L

I've found SRS (with Supermemo) is indispensable for learning vocabulary of languages in which immersion is not possible or too impractical e.g. ancient Greek/Latin. As you say, it requires discipline; but if something is important you'll find the time, if not you'll find an excuse.