Using colocort enema every 3 days to control inflammation from colitis in addition to asacol (mesalamine) daily. Is long time usage of colocort bad? No problem yet

Maybe. Colocort is a steroid medication. Although you are using it in limited fashion and in a topical form, there is still systemic absorption and, over time, steroid side effects can occur (bone loss, glucose intolerance, hip problems, cataracts, etc). Best to discuss your concerns with your provider to see if Mesalamine enemas would help or if you need a different steroid sparing medication.
It depends. I assume this treatment is directed by your gastroenterologist, and that you have been diagnosed with ulcerative colitis. If not, please consult with a gastroenterologist, as the term "colitis" alone is nonspecific. Ulcerative colitis is often treated with Asacol (mesalamine) long-term. Steroid enemas (such as colocort) are useful to control flares, but generally not recommended long-term.