diff --git a/src/registry.rs b/src/registry.rs
index 28fa30c..c7b1de5 100644
--- a/src/registry.rs
+++ b/src/registry.rs
@@ -2,14 +2,18 @@ use bevy_ecs::prelude::*;
 use std::any::TypeId;
 use std::collections::HashMap;
 
+/// A function used to merge effects with [`EffectMode::Merge`](crate::EffectMode::Merge), which must be registered in the [registry](EffectMergeRegistry).
 pub type EffectMergeFn = fn(world: &mut World, old: Entity, incoming: Entity);
 
+/// Stores the effect merge logic for each registered component.
+/// New components can be registered by providing a [`EffectMergeFn`] to the [`register`](EffectMergeRegistry::register) method.
 #[derive(Resource, Default)]
 pub struct EffectMergeRegistry {
     pub(crate) merges: HashMap<TypeId, EffectMergeFn>,
 }
 
 impl EffectMergeRegistry {
+    /// Registers a [`EffectMergeFn`] to be run whenever two `T` status effects are merged.
     pub fn register<T: Component>(&mut self, f: EffectMergeFn) -> &mut Self {
         self.merges.insert(TypeId::of::<T>(), f);
         self
diff --git a/src/timer.rs b/src/timer.rs
index 1acb9d1..9176283 100644
--- a/src/timer.rs
+++ b/src/timer.rs
@@ -17,6 +17,7 @@ impl Plugin for TimerPlugin {
     }
 }
 
+/// Registers the default merge logic for [`Lifetime`] and [`Delay`].
 pub fn register_timer_merge_functions(registry: &mut EffectMergeRegistry) {
     registry
         .register::<Lifetime>(merge_timer::<Lifetime>)