DON'T think you can do all your relatives in one day. It Notes to tape flags in the books. They damage the books. DON'T assume everything is cataloged. There may be some vertical files that haven't yet been cataloged.
Few libraries have unlimited funds.
DON'T put the books and microfilm away. I was greatly helped by Gwen Billingsly at the Rome-Floyd County Public Library. She not only knew her collection, but she gave me referrals to cemetery sextons, an archivist, and other genealogists in the county. She made my trip a spectacular success. Genealogists know a lot better than that.