Capex question

Hi guys,

Would you have a good resource that would explain how to analyze and interpret maintenance and growth Capex numbers please? This is rather confusing to me. 

For instance b say the average life of the assets is calculated at 6 years and average remaining years is 2 years: what does it tell us about the company? 

Is this to be looked at in isolation or over a multi year timeframe? (to see if the average life and remaining life have changed) 

What does it mean if maintenance vs growth Capex =80/20 or if maintenance Capex > Depreciation for instance.

Etc

Also: how to think of intangibles vs PPE? 

Thanks !