Spaced repetition is one of the most useful tools available to a beginner. It is also easy to turn it into the entire language-learning process.
That is a mistake.
Early learners have a repetition problem
When you know only a few hundred words, natural content cannot reliably show you every important item often enough to remember it. SRS solves that scarcity problem by deliberately bringing useful language back before it disappears.
This is especially valuable for high-frequency vocabulary. A relatively small core unlocks a disproportionate amount of later input, so protecting those early memories has a large payoff.
SRS is a bridge, not the destination
The purpose of remembering vocabulary is to understand and use language outside the review system. As reading and listening become easier, common words begin returning naturally in stories, conversations and media.
At that point, the environment starts doing some of the scheduling for you.
Do not build a review prison
Adding every unknown word creates enormous queues filled with low-value items. Review time then crowds out the very reading and listening that should eventually make formal review less necessary.
Prioritise useful language. Keep cards connected to meaningful sentences and audio. Let mature items go when natural exposure is carrying the load.
The role changes as you improve
Early: SRS helps manufacture repetition that the world cannot yet provide. Later: reading and listening supply far more varied repetition, while SRS becomes selective.
The best SRS system is one that helps you outgrow your dependence on SRS.