diff --git a/TODO.md b/TODO.md
index 0e407ad..a32acde 100644
--- a/TODO.md
+++ b/TODO.md
@@ -7,5 +7,5 @@ To-Do List
 - [ ] Flexible mandatory subjects
 
 ## v0.3
-- [ ] make script functional
+- [x] make script functional (sorta)
 - [ ] timetable editor (add & remove lessons, view timetable)
diff --git a/ib-clearance.py b/ib-clearance.py
index 3469c12..08592a9 100755
--- a/ib-clearance.py
+++ b/ib-clearance.py
@@ -28,30 +28,27 @@ def connect_database(file):
     return conn
 
 
-def get_lower_weekday():
+def request_id(conn):
     """
-    Returns current weekday's name as lowercase string.
-    """
-    day = time.strftime("%A")
-    lower_day = day.lower()
-    return lower_day
-
-
-def check_id(conn, id):
-    """
-    Returns True if existing ID, False if not.
+    Request student ID, validate, and return.
     :param conn: Connection object
-    :param id: ID of student, int
     """
-    cur = conn.cursor()
-    cur.execute("SELECT id FROM students")
-    ids = cur.fetchall()
+    try:
+        id = int(input("Please enter student ID: "))
 
-    for x in ids:
-        if id == x[0]:
-            return True
-    else:
-        return False
+        cur = conn.cursor()
+        cur.execute("SELECT id FROM students")
+        ids = cur.fetchall()
+
+        for x in ids:
+            # ids are single value tuples
+            if id == x[0]:
+                return id
+        else:
+            raise ValueError
+    except ValueError:
+        print("Incorrect ID, try again.")
+        request_id(conn)
 
 
 def select_final_time(conn, day, id):
@@ -86,7 +83,7 @@ def select_final_time(conn, day, id):
 
 def parse_time_string(timestring):
     """
-    Parses given 24h time string of format "HH:MM" into time_struct.
+    Parses given 24h time string of format "HH:MM" into struct_time.
     :param timestring: time string "HH:MM"
     """
     timestruct = time.strptime(timestring, "%H:%M")
@@ -96,35 +93,26 @@ def parse_time_string(timestring):
 def main():
     print("ib-clearance")
     print("============")
-    db = input(
-        "Please enter name of database (in same folder as program): ")
-    conn = connect_database(db)
 
-    y = "y"
-    while y == "y":
-        try:
-            id = int(input("Please input the student ID number: "))
+    conn = connect_database("database.db")
 
-            if check_id(conn, id):
-                day = get_lower_weekday()
-                raw_time = select_final_time(conn, day, id)
-                # if raw_time is None, student has no lessons today
-                if raw_time != None:
-                    final_time = parse_time_string(raw_time)
-                    current_time = parse_time_string(time.strftime("%H:%M"))
-                    if current_time > final_time:
-                        print("Clear to leave.")
-                    else:
-                        print("Student does not have clearance.")
-                elif raw_time == None:
-                    print("Clear to leave.")
-            else:
-                print("Student does not exist in the database. Please try again.")
-        except ValueError:
-            print("That was not an integer, please try again.")
+    while True:
+        id = request_id(conn)
+        day = time.strftime("%A").lower()
+        finish_time = select_final_time(conn, day, id)
+        current_time = time.strftime("%H:%M")
 
-        y = input("Press y key followed by enter to run again.")
+        if finish_time == None:
+            print("Student has no lessons today, clear to leave.")
+        elif parse_time_string(finish_time) < parse_time_string(current_time):
+            print("Student has finished for today, clear to leave.")
+        else:
+            print("Student still has lessons, clearance not granted.")
+
+        if input("Enter y to run again.") != "y":
+            break
 
 
+# Run main() if script is run standalone.
 if __name__ == "__main__":
     main()