Mine used to be constant, but over the past few months I have longer and longer periods without it. I have had tinnitus in ever changing forms for 20 months and I still think that one day mine will eventually go, or at least be quiet enough that I will almost never notice it. I enjoyed total silence twice this morning for 15 and 5 minutes.
Having said that, my tinnitus didn't start like anyone else I have ever encountered, nor is the suspected cause very common. As I've said to other people though, I don't think it does any harm to hope that it will go away, but at the same time, you need to continue to live your life with it.