I think if you're were having issues with narrowing, you would have more severe symptoms. Usually you will be unable to pass gas, and you would likely be experiencing fewer bowel movements.
It really depends on the severity of your disease. It sounds like you've only used 5-ASA's, which is the most mild of the medications of course.
The thing I would be concerned with, is going without any medication. The disease could progress without symptoms, then you could potentially end up with a severe complication, or permanent damage.
If you're going to go without med's. Then perhaps you should be going for regular blood work, and try to get your GI to schedule a regular MRE. Maybe twice a year.