(a) No exemption from taxation on the valuation of real property as provided in this subchapter shall be allowed except on written application therefor, which application shall be on a form prescribed by the governing bodies of the respective counties and provided for the use of the claimants under this subchapter by the governing body of the taxing district in which such claim is to be filed.
(b) An application for exemption under this subchapter shall be filed with the assessor of the taxing district by a date determined by the taxing district, which shall not be earlier than 45 days prior to the last date of the pre tax year; provided, however, that unless the income of the applicant has changed to exceed the $3,000 allowed, or unless the applicant no longer owns the dwelling which is a constituent part of the applicant's real property, or unless the applicant's spouse has income exceeding the $3,000 maximum, annual renewal shall not be required to qualify under this subchapter.