diff --git a/README.md b/README.md
index a998434..cd37b31 100644
--- a/README.md
+++ b/README.md
@@ -15,4 +15,3 @@ save nightly mysql database dumps
 
 ## To Do
 
-1. Expire old logs
diff --git a/mysqlbackup b/mysqlbackup
index a476992..3bc7065 100755
--- a/mysqlbackup
+++ b/mysqlbackup
@@ -3,41 +3,60 @@
 # This script will backup all mysql databases into 
 # compressed file named after date, ie: /var/backup/mysql/2016-07-13.tar.gz
 
-# Setup variables used later
 
 # Create date suffix with "F"ull date format
-suffix=$(date +%F)
+SUFFIX=$(date +%F)
+
 # Retrieve all database names except information schemas. 
-dbs=$(/usr/local/bin/mysql --defaults-extra-file=/root/.my.cnf --batch --skip-column-names -e "SHOW DATABASES;" | grep -E -v "(information|performance)_schema")
+DBS=$(/usr/local/bin/mysql \
+	--defaults-extra-file=/root/.my.cnf \
+	--batch \
+	--skip-column-names \
+	-e "SHOW DATABASES;" \
+	| grep -E -v "(information|performance)_schema")
+
 # Create temporary directory with "-d" option
-tmp=$(mktemp -d)
+TMP_DIR=$(mktemp -d)
+
 # Set output dir here. /var/backups/ is used by system, 
 # so intentionally used /var/backup/ for user backups.
-outDir="/var/backup/mysql"
-# Create output file name
-out="$outDir/$suffix.tar.gz"
+OUT_DIR="/var/backup/mysql"
+
+# Create output file name
+OUT_FILE="$OUT_DIR/$SUFFIX.tar.gz"
+
+# Number of days to save backups
+SAVE_DAYS=180
 
-# Actual script
 
 # Check if output directory exists
-if [ ! -d "$outDir" ];then
-  # Create directory with parent ("-p" option) directories
-  mkdir -p "$outDir"
+if [ ! -d "$OUT_DIR" ];then
+	# Create directory with parent ("-p" option) directories
+	mkdir -p "$OUT_DIR"
 fi
 
 # Loop through all databases
-for db in $dbs; do
-  # Dump database to temporary directory with file name same as database name + sql suffix
-  /usr/local/bin/mysqldump --defaults-extra-file=/root/.my.cnf --events --triggers --routines --set-gtid-purged=OFF --databases "$db" > "$tmp/$db.sql"
+for DB in $DBS; do
+	# Dump database to temporary directory with file name same as database name + sql suffix
+	/usr/local/bin/mysqldump \
+		--defaults-extra-file=/root/.my.cnf \
+		--events \
+		--triggers \
+		--routines \
+		--set-gtid-purged=OFF \
+		--databases "$DB" \
+		> "$TMP_DIR/$DB.sql"
 done
 
 # Go to tmp dir
-cd $tmp
+cd $TMP_DIR
 
 # Compress all dumps with gzip, discard any output to /dev/null
-tar -zcf "$out" * > "/dev/null"
+tar -zcf "$OUT_FILE" * > "/dev/null"
 
 # Cleanup
 cd "/tmp/"
-rm -rf "$tmp"
+rm -rf "$TMP_DIR"
 
+# Expire old backups
+find ${OUT_DIR} -mtime +${SAVE_DAYS} -type f -delete