Servicing/Belts

My 197 is approaching 45k miles.

Due a service in 4k.

Never missed a beat up to now, serviced every 12k, oil change etc.

I was wondering what else should have been in this time?, can't seem to find any guides/info as to when belts should be changed etc.

Reason I ask is sometimes when first starting the car, the alternator belt squeaks/ and normally dissapears, but recently has lasted much longer.

Any help would be good.