diff --git a/include/block.h b/include/block.h
index f1c9aff..555549c 100644
--- a/include/block.h
+++ b/include/block.h
@@ -24,6 +24,5 @@ int block_init(block *const block);
 int block_deinit(block *const block);
 int block_execute(block *const block, const uint8_t button);
 int block_update(block *const block);
-bool block_must_run(const block *const block, const unsigned int time);
 
 #endif  // BLOCK_H
diff --git a/include/cli.h b/include/cli.h
index 3d2d5a5..2f93f62 100644
--- a/include/cli.h
+++ b/include/cli.h
@@ -7,7 +7,6 @@ typedef struct {
     bool is_debug_mode;
 } cli_arguments;
 
-int cli_init(cli_arguments* const args, const char* const argv[],
-             const int argc);
+cli_arguments cli_parse_arguments(const char* const argv[], const int argc);
 
 #endif  // CLI_H
diff --git a/include/timer.h b/include/timer.h
index eccf4a1..1ec7f75 100644
--- a/include/timer.h
+++ b/include/timer.h
@@ -2,6 +2,7 @@
 #define TIMER_H
 
 #include <signal.h>
+#include <stdbool.h>
 
 #include "block.h"
 
@@ -15,5 +16,6 @@ typedef struct {
 
 timer timer_new(const block *const blocks, const unsigned short block_count);
 int timer_arm(timer *const timer);
+bool timer_must_run_block(const timer *const timer, const block *const block);
 
 #endif  // TIMER_H
diff --git a/src/block.c b/src/block.c
index 5020b02..0a73af6 100644
--- a/src/block.c
+++ b/src/block.c
@@ -144,15 +144,3 @@ int block_update(block *const block) {
 
     return 0;
 }
-
-bool block_must_run(const block *const block, const unsigned int time) {
-    if (time == 0) {
-        return true;
-    }
-
-    if (block->interval == 0) {
-        return false;
-    }
-
-    return time % block->interval == 0;
-}
diff --git a/src/cli.c b/src/cli.c
index 1a48863..b1849ec 100644
--- a/src/cli.c
+++ b/src/cli.c
@@ -1,19 +1,22 @@
 #include "cli.h"
 
+#include <errno.h>
 #include <getopt.h>
 #include <stdbool.h>
 #include <stdio.h>
 
-int cli_init(cli_arguments *const args, const char *const argv[],
-             const int argc) {
-    args->is_debug_mode = false;
+cli_arguments cli_parse_arguments(const char *const argv[], const int argc) {
+    errno = 0;
+    cli_arguments args = {
+        .is_debug_mode = false,
+    };
 
     int opt = -1;
     opterr = 0;  // Suppress getopt's built-in invalid opt message
     while ((opt = getopt(argc, (char *const *)argv, "dh")) != -1) {
         switch (opt) {
             case 'd':
-                args->is_debug_mode = true;
+                args.is_debug_mode = true;
                 break;
             case '?':
                 (void)fprintf(stderr, "error: unknown option `-%c'\n", optopt);
@@ -22,9 +25,9 @@ int cli_init(cli_arguments *const args, const char *const argv[],
                 // fall through
             default:
                 (void)fprintf(stderr, "usage: %s [-d]\n", BINARY);
-                return 1;
+                errno = 1;
         }
     }
 
-    return 0;
+    return args;
 }
diff --git a/src/main.c b/src/main.c
index a858d88..4484f0a 100644
--- a/src/main.c
+++ b/src/main.c
@@ -1,5 +1,6 @@
 #include "main.h"
 
+#include <errno.h>
 #include <stdbool.h>
 #include <stddef.h>
 
@@ -38,10 +39,10 @@ static int deinit_blocks(block *const blocks,
 
 static int execute_blocks(block *const blocks,
                           const unsigned short block_count,
-                          const unsigned int time) {
+                          const timer *const timer) {
     for (unsigned short i = 0; i < block_count; ++i) {
         block *const block = &blocks[i];
-        if (!block_must_run(block, time)) {
+        if (!timer_must_run_block(timer, block)) {
             continue;
         }
 
@@ -55,7 +56,7 @@ static int execute_blocks(block *const blocks,
 
 static int trigger_event(block *const blocks, const unsigned short block_count,
                          timer *const timer) {
-    if (execute_blocks(blocks, block_count, timer->time) != 0) {
+    if (execute_blocks(blocks, block_count, timer) != 0) {
         return 1;
     }
 
@@ -117,8 +118,8 @@ static int event_loop(block *const blocks, const unsigned short block_count,
 }
 
 int main(const int argc, const char *const argv[]) {
-    cli_arguments cli_args;
-    if (cli_init(&cli_args, argv, argc) != 0) {
+    const cli_arguments cli_args = cli_parse_arguments(argv, argc);
+    if (errno != 0) {
         return 1;
     }
 
diff --git a/src/timer.c b/src/timer.c
index a9a383c..2454fb9 100644
--- a/src/timer.c
+++ b/src/timer.c
@@ -1,6 +1,7 @@
 #include "timer.h"
 
 #include <errno.h>
+#include <stdbool.h>
 #include <stdio.h>
 #include <unistd.h>
 
@@ -32,10 +33,12 @@ static unsigned int compute_reset_value(const block *const blocks,
 }
 
 timer timer_new(const block *const blocks, const unsigned short block_count) {
+    const unsigned int reset_value = compute_reset_value(blocks, block_count);
+
     timer timer = {
-        .time = 0,
+        .time = reset_value,  // Initial value to execute all blocks.
         .tick = compute_tick(blocks, block_count),
-        .reset_value = compute_reset_value(blocks, block_count),
+        .reset_value = reset_value,
     };
 
     return timer;
@@ -51,7 +54,19 @@ int timer_arm(timer *const timer) {
     }
 
     // Wrap `time` to the interval [1, reset_value].
-    timer->time = (timer->time + timer->tick) % timer->reset_value + 1;
+    timer->time = (timer->time + timer->tick) % timer->reset_value;
 
     return 0;
 }
+
+bool timer_must_run_block(const timer *const timer, const block *const block) {
+    if (timer->time == timer->reset_value) {
+        return true;
+    }
+
+    if (block->interval == 0) {
+        return false;
+    }
+
+    return timer->time % block->interval == 0;
+}