It makes sense to try the meds with the least potential for serious side effects, first. BUT stick with them only if they provide full remission.
If they don't, then go up the ladder of the pyramid (link to pic below) to find a med that, as much as possible, stops Crohn's dead in its tracks.
http://www.hopkins-gi.org/GDL_Disease.aspx?CurrentUDV=31&GDL_Cat_id=AF793A59-B736-42CB-9E1F-E79D2B9FC358&GDL_Disease_id=291F2209-F8A9-4011-8094-11EC9BF3100E
I don't believe the disease should be allowed to fester, even mildly - the potential for permanent strictures, also for fistulas, abcesses, etc, is just too big.
Right now, my daughter is on LDN, but if we get even a hint that there is some festering, still, then she will make a change.