If your landlord is answering your requests to make repairs, it is unlikely that not giving you 24 hour notice beforehand is justification for you to break your lease without the risk of financial penalty. Your landlord would likely argue (in court) that he is attempting to keep the rental unit safe for you by responding quickly to address repairs.
The 24 hour notice requirement is a bit arbitrary; it is an attempt to prevent landlords from simply walking in on tenants any time day or night. Coming over without notice twice is not likely to be seen by a judge as violating your right to a "quiet enjoyment".
Gail