From -
http://www.mindef.gov.sg/display.asp?number=1784
With effect from April 2003, a revised National Service (NS)
training system has been introduced for Operationally Ready
National Servicemen (NSmen).
Under the previous NS training system, NSmen had to perform 13
years of NS training, of which, at least nine must be high-key
in-camp training (ICT). With the revised NS training system, the
majority of NSmen will only need to serve at least seven high-key
ICTs. A two-day Basic Individual Training (BIT) programme that
focuses on physical fitness, marksmanship and refresher training
has also been introduced in the last three years of their 13 years
of NS training. This ensures that NSmen maintain their currency in
basic soldiering skills. Mobilisation exercises will also be
conducted during the BIT phase to maintain operational
readiness......
more from the link......