Please consult your doctor - On the Mucinex 600 mg guaifenesin-only extended release version, it says: "Stop use and ask a doctor if cough lasts more than 7 days, comes back, or occurs with fever, rash, or persistent headache. These could be signs of a serious illness." If it is working for you, it is likely the doctor will tell you to keep using it as needed.

I have take guaifenesin daily for over 35 years without any issues. When I first started, it was a prescription, generic & very cheap. and my ENT at the time said he had used it for years himself... Now it is over-the-counter, Mucinex held the patent on the long-acting version for years, and there are finally cheaper generics coming.

Also, vaporizers are great - just be sure to use a steam one, or if you use a cold one, to clean it scrupulously at least once a week. Otherwise, they can be breeding grounds for lots of nasty bacteria & spray it into the air.
Sue