diff --git a/backup.py b/backup.py
index 6a1d55d..5758e06 100755
--- a/backup.py
+++ b/backup.py
@@ -46,7 +46,15 @@ loglvls = {'critical': logging.CRITICAL,
 dflt_ns = 'http://git.root2.io/r00t2/borgextend/'
 
 # In code, replace "day" with "daily" when constructing command.
-policyperiods = ('Second', 'Minute', 'Hour', 'Day', 'Week', 'Month', 'Year')
+policyperiods = (
+    ('seconds', 'secondly'),
+    ('minutes', 'minutely'),
+    ('hours', 'hourly'),
+    ('days', 'daily'),
+    ('weeks', 'weekly'),
+    ('months', 'monthly'),
+    ('years', 'yearly'),
+    )
 
 ### THE GUTS ###
 class Backup(object):
@@ -170,14 +178,13 @@ class Backup(object):
                     r['retention']['last'] = isodate.parse_duration(keepWithin.text)
                 keepLast = repo.find('{0}keepLast'.format(self.ns))
                 if keepLast is not None:
-                    for e in policyperiods:
-                        k = e.lower()
-                        policy = keepLast.find('{0}per{1}'.format(self.ns, e))
+                    for e, _ in policyperiods:
+                        policy = keepLast.find('{0}{1}'.format(self.ns, e))
                         if policy is not None:
                             if 'retention' not in r.keys():
                                 r['retention'] = {}
                             # This is safe. We validate the config.
-                            r['retention'][k] = int(policy.text)
+                            r['retention'][e] = int(policy.text)
                 repos.append(r)
             return(repos)
         self.logger.debug('VARS (before args cleanup): {0}'.format(vars(self)))
@@ -514,12 +521,9 @@ class Backup(object):
                         retentionSeconds = repo['retention'].totimedelta(datetime.datetime.now()).total_seconds()
                     _cmd.extend(['--keep-within',  '{0}H'.format(retentionSeconds / 60)])
                 # keepLast
-                for e in policyperiods:
-                    if repo['retention'].get(e.lower()) is not None:
-                        a = e.lower() + 'ly'
-                        if e.lower() == 'day':
-                            a = 'daily'
-                        _cmd.extend(['--keep-{0}'.format(a), repo['retention'][e.lower()]])
+                for e, a in policyperiods:
+                    if repo['retention'].get(e, 0) is not 0:
+                        _cmd.extend(['--keep-{0}'.format(a), repo['retention'][e]])
                 if self.repos[server]['remote'].lower()[0] in ('1', 't'):
                     repo_tgt = '{0}@{1}'.format(_user, server)
                 else:
diff --git a/config.xsd b/config.xsd
index f9cc0e1..b1472ea 100644
--- a/config.xsd
+++ b/config.xsd
@@ -64,13 +64,13 @@
                     <xs:element name="keepLast" minOccurs="0" maxOccurs="1">
                       <xs:complexType>
                         <xs:choice minOccurs="1" maxOccurs="7">
-                          <xs:element name="perSecond" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
-                          <xs:element name="perMinute" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
-                          <xs:element name="perHour" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
-                          <xs:element name="perDay" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
-                          <xs:element name="perWeek" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
-                          <xs:element name="perMonth" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
-                          <xs:element name="perYear" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
+                          <xs:element name="seconds" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
+                          <xs:element name="minutes" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
+                          <xs:element name="hours" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
+                          <xs:element name="days" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
+                          <xs:element name="weeks" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
+                          <xs:element name="months" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
+                          <xs:element name="years" minOccurs="0" maxOccurs="1" type="xs:positiveInteger"/>
                         </xs:choice>
                       </xs:complexType>
                     </xs:element>
diff --git a/sample.config.xml b/sample.config.xml
index 86ce93d..e33964a 100644
--- a/sample.config.xml
+++ b/sample.config.xml
@@ -41,12 +41,12 @@
             <keepWithin>P1MT2M30S</keepWithin>
             <!--
                 keepLast specifies a *policy* for retention.
-                It can be used to specify explicit "N archives per Y". For example, the below retains the first
-                archive for each month (going back 2 months), and the first archive each year for the last three years.
+                It can be used to specify explicit "N archives per Y period type". For example, the below retains the last
+                archive for each month (going back 2 months), and the last archive each year for the last three years.
             -->
             <keepLast>
-                <perMonth>2</perMonth>
-                <perYear>3</perYear>
+                <months>2</months>
+                <years>3</years>
             </keepLast>
             <!--
                 Each path entry is a path to back up.