Just a quick one, At what age do you start to scout and train a new driver? i know the age doesn't affect performance I'm assuming it's just a personal preference.
Others may have different opinions but AFAIK drivers performance no longer deteriorates with age so you can choose to either keep them until they retire or until their wage demands become too high.
If you're keeping them until retirement, they will announce this immediately after you renew their contract which gives you 50 races to train an academy driver to replace them.