Hi,
You only need one for when you shut the engine off after a bit of a slog with the thing. Just around town etc they are unneccessary. I have had several Tdi Discos and NEVER bothered with a timer and I lived at the top of a steep hill. All I did was wait 30" to 60" and shut it down. Usually enuf time to go unlock the house or finish listening to ya fav ABBA song on the wireless
Just my 10c (that's the smallest coin we have now
)