The CERF language levels are A1, A2, B1, B2, C1 and C2. A1 is the lowest level, and C2 is more or less native.
I read somewhere that it takes twice as long to reach level B2 from level B1, as it does to reach A2 from A1. I also read that it takes twice as long to reach level C1 from B2, as it did to reach level B2 from B1.
In other words, the time needed to move up a level doubles each time.
This has certainly been my experience and I’ve now started on the long, long, long journey from a faltering B2 in Italian to C1. At this rate it will take me another four years … not that there is any hurry.
The good news is that you don’t need to spend any money to do this. Find people to talk to, and listen to pod casts for native speakers. Rince and repeat:)
Just do a little every day, and you will improve.
Or so I keep telling myself … Sono troppo pigro …
Of course, producers of language courses don’t want you to know that you can progress very comfortably without following any course, particularly as you become more advanced.