diff --git a/lib/index.js b/lib/index.js
index 7a8d5eb..b382baa 100644
--- a/lib/index.js
+++ b/lib/index.js
@@ -26,7 +26,7 @@ const makeDebug = require('debug')
  * @param {{ db: PPPPPDB | null }} peer
  * @returns {asserts peer is { db: PPPPPDB }}
  */
-function assertDBExists(peer) {
+function assertDBPlugin(peer) {
   if (!peer.db) throw new Error('gc plugin requires ppppp-db plugin')
 }
 
@@ -34,7 +34,7 @@ function assertDBExists(peer) {
  * @param {{ goals: PPPPPGoal | null }} peer
  * @returns {asserts peer is { goals: PPPPPGoal }}
  */
-function assertGoalsExists(peer) {
+function assertGoalsPlugin(peer) {
   if (!peer.goals) throw new Error('gc plugin requires ppppp-goals plugin')
 }
 
@@ -54,8 +54,8 @@ function assertValidConfig(config) {
  */
 function initGC(peer, config) {
   // Assertions
-  assertDBExists(peer)
-  assertGoalsExists(peer)
+  assertDBPlugin(peer)
+  assertGoalsPlugin(peer)
   assertValidConfig(config)
 
   // Constants
@@ -74,8 +74,8 @@ function initGC(peer, config) {
    * @param {CB<void>} cb
    */
   function cleanup(cb) {
-    assertDBExists(peer)
-    assertGoalsExists(peer)
+    assertDBPlugin(peer)
+    assertGoalsPlugin(peer)
     debug('cleanup-per-purpose started')
 
     const done = multicb({ pluck: 1 })
@@ -120,7 +120,7 @@ function initGC(peer, config) {
    * @param {CB<void>} cb
    */
   function compact(waitPeriod, cb) {
-    assertDBExists(peer)
+    assertDBPlugin(peer)
     const log = peer.db._getLog() // TODO: use public API?
     debug('compaction started')
     /** @param {Error=} err */
@@ -140,9 +140,9 @@ function initGC(peer, config) {
    * Monitor the log size and schedule compaction and/or cleanup.
    */
   function monitorLogSize() {
-    assertDBExists(peer)
+    assertDBPlugin(peer)
     function checkLogSize() {
-      assertDBExists(peer)
+      assertDBPlugin(peer)
       assertValidConfig(config)
       peer.db.logStats((err, stats) => {
         if (err) return