National Service (NS) refers to the 2 years one must serve when
he is 18 years old or above.
the 10 years of reservist training after ORD is not called National
Service. it is called Operation Ready Service (ORNS).
to clear things up, for non-commission officers, one must serve
till 40 years old. each year one may be called up for a maximum of
40 days.
if your unit call u back every year, u can easily complete your 10
ICTs by 30+ years old. and even if your unit didn't call u back for
a long time, u will still ROD at age 40 regardless of whether u
completed 10 ICTs or not.
