The finances of the municipality shall be conducted upon an annual budget as required by law, which shall be adopted by the Council as required by law. For the purpose of the budget, each office, department or agency of the municipality shall furnish to the manager, at such times and in such forms as he may require, estimates of revenue and expenditures of that office, department or agency and such other supporting data as the manager may request; together with an estimate of all capital projects pending or which the head of each office, department or agency believes should be undertaken (a) within the succeeding fiscal year, and (b) within the 5 next succeeding years. The manager may review such estimates, conduct hearings in connection therewith and make such revisions as he may deem advisable.