You can stay on suboxone forever if you choose, whether it is for chronic pain or for opiate addiction / dependency. It doesn't offer as good of pain relief, but it also doesn't have a lot of the negatives those other opiates do. You don't get tolerant of suboxone either, so your dose would never have to go up...in fact you could easily taper to 4 mg over a several month process and feel just as good most likely.
Both my primary care Dr. & my suboxone Dr, whom is a psychiatrist, want me to stay on it forever, but i choose to at least try and get off of it. I started where you are , at 8 mg a day (was prescribed 20 mg) and have weaned down to 1.3 mg a day, over the course of a year. It's mighty powerful stuff!
Hope that helps
PS...I just noticed you are from S. Africa so perhaps things are different there, but this is how it is in the U.S., and normally consists of seeing a dr. 1x a month for a refill, unless you are in an outpatient program, then you may be more restricted on your prescription.