If an airline has a regular schedule I really dont see why that airline cannot get a roster produced in plenty of time for the following month, why should a roster produced in plenty of time have any cost implications for a company as opposed to a roster produced at the last minute, it appears to me that it has more to do with a badly organised rostering department.
Whatever 411 thinks, a company does have a responsibility towards its aircrew employees to provide some sort of stable work pattern.
A roster produced in plenty of time so one can plan ones life outside aviation is very important especially those with families, it can make the difference between happy employees with a good home life and miserable divorced ones without one.
In the main I enjoy my aviation career but I am entitled to a life outside of it. Our company is obviously very good compared to others, we have a roster produced on the 10th of each month for the four weeks ahead with new agreements in place to stop it being altered at short notice, if it is then we can be compensated for the changes