diff --git a/ChangeLog b/ChangeLog
index 2de9d4e..f723e9e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+* 0.4.2
+- Added the pad_expiration option which tells pam_usb how often pads
+  should be updated in order to reduce device writing.
+- Support for time options in the configuration parser (5s, 2h, 10m, etc)
+
 * 0.4.1
 - Fixed a security issue related to OpenSSH authentication
 - Fixed the quiet option (now it is really quiet)
diff --git a/src/conf.c b/src/conf.c
index 8775809..2457dad 100644
--- a/src/conf.c
+++ b/src/conf.c
@@ -44,7 +44,9 @@ static void pusb_conf_options_get_from(t_pusb_options *opts,
 			&(opts->enable));
 	pusb_xpath_get_bool_from(doc, from, "option[@name='one_time_pad']",
 			&(opts->one_time_pad));
-	pusb_xpath_get_int_from(doc, from, "option[@name='probe_timeout']",
+	pusb_xpath_get_time_from(doc, from, "option[@name='pad_expiration']",
+			&(opts->pad_expiration));
+	pusb_xpath_get_time_from(doc, from, "option[@name='probe_timeout']",
 			&(opts->probe_timeout));
 }
 
@@ -136,6 +138,7 @@ int pusb_conf_init(t_pusb_options *opts)
 	opts->quiet = 0;
 	opts->color_log = 1;
 	opts->one_time_pad = 1;
+	opts->pad_expiration = 86400;
 	return (1);
 }
 
diff --git a/src/conf.h b/src/conf.h
index 4570048..d2dae23 100644
--- a/src/conf.h
+++ b/src/conf.h
@@ -24,6 +24,7 @@
 # define CONF_USER_MAXLEN 32
 # include <limits.h>
 # include <linux/limits.h>
+# include <sys/time.h>
 # ifndef PATH_MAX
 #  define PATH_MAX 4096
 # endif
@@ -39,12 +40,13 @@ typedef struct	pusb_device
 
 typedef struct		pusb_options
 {
-	int				probe_timeout;
+	time_t			probe_timeout;
 	int				enable;
 	int				debug;
 	int				quiet;
 	int				color_log;
 	int				one_time_pad;
+	time_t			pad_expiration;
 	char			hostname[32];
 	char			system_pad_directory[PATH_MAX];
 	char			device_pad_directory[PATH_MAX];
diff --git a/src/pad.c b/src/pad.c
index 88d0fab..ff73a74 100644
--- a/src/pad.c
+++ b/src/pad.c
@@ -135,6 +135,49 @@ static int pusb_pad_protect(const char *user, int fd)
 	return (1);
 }
 
+static int pusb_pad_should_update(t_pusb_options *opts, const char *user)
+{
+	FILE		*f_system = NULL;
+	struct stat st;
+	time_t		now;
+	time_t		delta;
+
+	log_debug("Checking whether pads are expired or not...");
+	if (!(f_system = pusb_pad_open_system(opts, user, "r")))
+	{
+		log_debug("Unable to open system pad, pads must be generated.\n");
+		return (1);
+	}
+	if (fstat(fileno(f_system), &st) == -1)
+	{
+		fclose(f_system);
+		return (1);
+	}
+	fclose(f_system);
+
+	if (time(&now) == ((time_t)-1))
+	{
+		log_error("Unable to fetch current time.\n");
+		return (1);
+	}
+
+	delta = now - st.st_mtime;
+
+	if (delta > opts->pad_expiration)
+	{
+		log_info("Pads expired %u seconds ago, updating...\n",
+				delta - opts->pad_expiration);
+		return (1);
+	}
+	else
+	{
+		log_info("Pads were generated %u seconds ago, not updating.\n",
+				delta);
+		return (0);
+	}
+	return (1);
+}
+
 static void pusb_pad_update(t_pusb_options *opts,
 		LibHalVolume *volume,
 		const char *user)
@@ -144,12 +187,15 @@ static void pusb_pad_update(t_pusb_options *opts,
 	char	magic[1024];
 	int		i;
 
+	if (!pusb_pad_should_update(opts, user))
+		return ;
 	if (!(f_device = pusb_pad_open_device(opts, volume, user, "w+")))
 	{
 		log_error("Unable to update pads.\n");
 		return ;
 	}
 	pusb_pad_protect(user, fileno(f_device));
+
 	if (!(f_system = pusb_pad_open_system(opts, user, "w+")))
 	{
 		log_error("Unable to update pads.\n");
@@ -157,6 +203,7 @@ static void pusb_pad_update(t_pusb_options *opts,
 		return ;
 	}
 	pusb_pad_protect(user, fileno(f_system));
+
 	log_debug("Generating %d bytes unique pad...\n", sizeof(magic));
 	srand(getpid() * time(NULL));
 	for (i = 0; i < sizeof(magic); ++i)
diff --git a/src/pamusb-check.c b/src/pamusb-check.c
index 6f8772f..b8b8e0b 100644
--- a/src/pamusb-check.c
+++ b/src/pamusb-check.c
@@ -35,7 +35,8 @@ static void pusb_check_conf_dump(t_pusb_options *opts, const char *username,
 	fprintf(stdout, "color_log\t\t: %s\n", opts->color_log ? "true" : "false");
 	fprintf(stdout, "one_time_pad\t\t: %s\n",
 			opts->one_time_pad ? "true" : "false");
-	fprintf(stdout, "probe_timeout\t\t: %d\n", opts->probe_timeout);
+	fprintf(stdout, "pad_expiration\t\t: %u seconds\n", (unsigned int)opts->pad_expiration);
+	fprintf(stdout, "probe_timeout\t\t: %d seconds\n", (unsigned int)opts->probe_timeout);
 	fprintf(stdout, "hostname\t\t: %s\n", opts->hostname);
 	fprintf(stdout, "system_pad_directory\t: %s\n",
 			opts->system_pad_directory);
diff --git a/src/xpath.c b/src/xpath.c
index cd2ffeb..27b88c8 100644
--- a/src/xpath.c
+++ b/src/xpath.c
@@ -179,14 +179,66 @@ int pusb_xpath_get_bool_from(xmlDocPtr doc,
 	snprintf(xpath, xpath_size, "%s%s", base, path);
 	retval = pusb_xpath_get_bool(doc, xpath, value);
 	free(xpath);
-	if (retval)
-		log_debug("%s%s -> %s\n", base, path, *value ? "true" : "false");
+	return (retval);
+}
+
+int pusb_xpath_get_time(xmlDocPtr doc, const char *path, time_t *value)
+{
+	char	ret[64];
+	char	*last;
+	int		coef;
+
+	if (!pusb_xpath_get_string(doc, path, ret, sizeof(ret)))
+		return (0);
+
+	last = &(ret[strlen(ret) - 1]);
+	coef = 1;
+	if (*last == 's')
+		coef = 1;
+	else if (*last == 'm')
+		coef = 60;
+	else if (*last == 'h')
+		coef = 3600;
+	else if (*last == 'd')
+		coef = 3600 * 24;
+	else
+		if (!isdigit(*last))
+		{
+			log_debug("Expecting a time modifier, got %c\n", *last);
+			return (0);
+		}
+	if (!isdigit(*last))
+		*last = '\0';
+	*value = atoi(ret) * coef;
+
+	return (0);
+}
+
+int pusb_xpath_get_time_from(xmlDocPtr doc,
+		const char *base,
+		const char *path,
+		time_t *value)
+{
+	char	*xpath = NULL;
+	size_t	xpath_size;
+	int		retval;
+
+	xpath_size = strlen(base) + strlen(path) + 1;
+	if (!(xpath = malloc(xpath_size)))
+	{
+		log_error("malloc error!\n");
+		return (0);
+	}
+	memset(xpath, 0x00, xpath_size);
+	snprintf(xpath, xpath_size, "%s%s", base, path);
+	retval = pusb_xpath_get_time(doc, xpath, value);
+	free(xpath);
 	return (retval);
 }
 
 int pusb_xpath_get_int(xmlDocPtr doc, const char *path, int *value)
 {
-	char	ret[64]; /* strlen("false") + 1 */
+	char	ret[64];
 
 	if (!pusb_xpath_get_string(doc, path, ret, sizeof(ret)))
 		return (0);
@@ -213,7 +265,5 @@ int pusb_xpath_get_int_from(xmlDocPtr doc,
 	snprintf(xpath, xpath_size, "%s%s", base, path);
 	retval = pusb_xpath_get_int(doc, xpath, value);
 	free(xpath);
-	if (retval)
-		log_debug("%s%s -> %d\n", base, path, *value);
 	return (retval);
 }
diff --git a/src/xpath.h b/src/xpath.h
index fd6995d..1a74cbc 100644
--- a/src/xpath.h
+++ b/src/xpath.h
@@ -20,9 +20,11 @@
 # include <libxml/parser.h>
 
 int pusb_xpath_get_string(xmlDocPtr doc, const char *path, char *value, size_t size);
-int pusb_xpath_get_bool(xmlDocPtr doc, const char *path, int *value);
 int pusb_xpath_get_string_from(xmlDocPtr doc, const char *base, const char *path, char *value, size_t size);
+int pusb_xpath_get_bool(xmlDocPtr doc, const char *path, int *value);
 int pusb_xpath_get_bool_from(xmlDocPtr doc, const char *base, const char *path, int *value);
+int pusb_xpath_get_time(xmlDocPtr doc, const char *path, time_t *value);
+int pusb_xpath_get_time_from(xmlDocPtr doc, const char *base, const char *path, time_t *value);
 int pusb_xpath_get_int(xmlDocPtr doc, const char *path, int *value);
 int pusb_xpath_get_int_from(xmlDocPtr doc, const char *base, const char *path, int *value);