I have a 2003 323f 1.6 Gsi Auto with a ZM engine which has done 51,000 carefully driven miles. I had a new timing belt fitted by a Mazda dealer in January 2012 at 38,00 miles, on the basis that the car was 8 years old.

I only do about 1,000 miles a year now,but as it's almost 8 years since that one was fitted, and it's only done 13,000 miles since the last one, I'm unsure whether a replacement is really necessary. The water pump and auxilliary belt are the originals and it has been regularly serviced.

I hope to keep the car as long as long as I am able to drive and would welcome any opinions on a new belt and and auxilliary items.

Althought the belt hasn't turn alot, it ages with time.Then when you drive the car it start to lose it's properties and to crack and could lead to failure.
If you want to rely on the car, change it.
Cheers!

Technically the replacement cycle is 54,000 miles, with no time limit specified. But, as mazzda says above, it's a good idea to replace it.