What are the responsibilities of a Project Manager on a remodel?

What are the responsibilities of a Project Manager? I have asked for a kitchen, bedroom and two bath remodel in a small 1400 sq ft house and needed similar recessed cabinets I had in bathrooms, for example, due to little storage/space and did not get any. Rotten wood was covered in several places by new vinyl siding and wall trim had to be repainted due to colors not being communicated to sub contractors. Existing bath fixtures and wood shelving that were going to be used were tossed. The project cost was about 1/4 more than quoted and contractor fee was $20k on top of cost and they never got to the kitchen. Thank goodness there were no structural issues or any problems when walls were opened up. Needless to say that having to take money out of my retirement twice has drained my funds and now I will not be retiring when I thought I could. What should I have done differently? Thanks in advance for any advice and words of wisdom.

A good Project Manager will schedule and co-ordinate the various contractors involved in a project, schedule material drops, meet with inspectors, act as a liaison between client - contractors ect. This frees up time for contractors to move ahead on project thus expiditing the whole project.