diff --git a/client.js b/client.js
index bfe8ee5..0d12422 100644
--- a/client.js
+++ b/client.js
@@ -48,7 +48,7 @@ function Client (peerId, port, torrent, opts) {
   self._numWant = self._opts.numWant || 50
   self._intervalMs = self._opts.interval || (30 * 60 * 1000) // default: 30 minutes
 
-  debug('new tracker client for ' + self._infoHash.toString('hex'))
+  debug('new client %s', self._infoHash.toString('hex'))
 
   if (typeof torrent.announce === 'string') {
     // magnet-uri returns a string if the magnet uri only contains one 'tr' parameter
@@ -148,7 +148,7 @@ function Tracker (client, announceUrl, opts) {
 
   self.client = client
 
-  debug('new tracker for ' + announceUrl)
+  debug('new tracker %s', announceUrl)
 
   self._announceUrl = announceUrl
   self._intervalMs = self.client._intervalMs // use client interval initially
@@ -166,7 +166,7 @@ Tracker.prototype.start = function (opts) {
   opts = opts || {}
   opts.event = 'started'
 
-  debug('sent `start` to ' + self._announceUrl)
+  debug('sent `start` %s', self._announceUrl)
   self._announce(opts)
   self.setInterval(self._intervalMs) // start announcing on intervals
 }
@@ -176,7 +176,7 @@ Tracker.prototype.stop = function (opts) {
   opts = opts || {}
   opts.event = 'stopped'
 
-  debug('sent `stop` to ' + self._announceUrl)
+  debug('sent `stop` %s', self._announceUrl)
   self._announce(opts)
   self.setInterval(0) // stop announcing on intervals
 }
@@ -187,7 +187,7 @@ Tracker.prototype.complete = function (opts) {
   opts.event = 'completed'
   opts.downloaded = opts.downloaded || self.torrentLength || 0
 
-  debug('sent `complete` to ' + self._announceUrl)
+  debug('sent `complete` %s', self._announceUrl)
   self._announce(opts)
 }
 
@@ -195,7 +195,7 @@ Tracker.prototype.update = function (opts) {
   var self = this
   opts = opts || {}
 
-  debug('sent `update` to ' + self._announceUrl)
+  debug('sent `update` %s', self._announceUrl)
   self._announce(opts)
 }
 
@@ -229,12 +229,12 @@ Tracker.prototype.scrape = function () {
   self._scrapeUrl = self._scrapeUrl || getScrapeUrl(self._announceUrl)
 
   if (!self._scrapeUrl) {
-    debug('scrape not supported by ' + self._announceUrl)
+    debug('scrape not supported %s', self._announceUrl)
     self.client.emit('error', new Error('scrape not supported for announceUrl ' + self._announceUrl))
     return
   }
 
-  debug('sent `scrape` to ' + self._announceUrl)
+  debug('sent `scrape` %s', self._announceUrl)
   self._requestImpl(self._scrapeUrl, { _scrape: true })
 }
 
diff --git a/server.js b/server.js
index 4a733a3..649e64c 100644
--- a/server.js
+++ b/server.js
@@ -235,7 +235,7 @@ Server.prototype._onHttpRequest = function (req, res) {
       response['warning message'] = warning
     }
     res.end(bencode.encode(response))
-    debug('sent response ' + response)
+    debug('sent response %s', response)
 
   } else if (s[0] === '/scrape') { // unofficial scrape message
     if (typeof params.info_hash === 'string') {
@@ -270,14 +270,14 @@ Server.prototype._onHttpRequest = function (req, res) {
     })
 
     res.end(bencode.encode(response))
-    debug('sent response ' + response)
+    debug('sent response %s', response)
 
   } else {
     error('only /announce and /scrape are valid endpoints')
   }
 
   function error (message) {
-    debug('sent error ' + message)
+    debug('sent error %s', message)
     res.end(bencode.encode({
       'failure reason': message
     }))
@@ -447,7 +447,7 @@ Server.prototype._onUdpRequest = function (msg, rinfo) {
   }
 
   function send (buf) {
-    debug('sent response ' + buf)
+    debug('sent response %s', buf.toString('hex'))
     socket.send(buf, 0, buf.length, rinfo.port, rinfo.address, function () {
       try {
         socket.close()
@@ -456,7 +456,7 @@ Server.prototype._onUdpRequest = function (msg, rinfo) {
   }
 
   function error (message) {
-    debug('sent error ' + message)
+    debug('sent error %s', message)
     send(Buffer.concat([
       common.toUInt32(common.ACTIONS.ERROR),
       common.toUInt32(transactionId || 0),