diff --git a/specs/validator/0_beacon-chain-validator.md b/specs/validator/0_beacon-chain-validator.md
index 36f26fea6..0d3854e8f 100644
--- a/specs/validator/0_beacon-chain-validator.md
+++ b/specs/validator/0_beacon-chain-validator.md
@@ -361,7 +361,7 @@ def get_next_epoch_crosslink_committees(state: BeaconState,
     return potential_assignments
 ```
 
-A validator should always plan for both values of `registry_change` as a possibility unless the validator can concretely eliminate one of the options. Planning for a future shuffling involves noting at which slot one might have to attest and propose and also which shard one should begin syncing (in phase 1+).
+`get_next_epoch_crosslink_committees` should be called at the beginning of each epoch to plan for the next epoch. A validator should always plan for both values of `registry_change` as a possibility unless the validator can concretely eliminate one of the options. Planning for a future shuffling involves noting at which slot one might have to attest and propose and also which shard one should begin syncing (in phase 1+).
 
 ## How to avoid slashing