Each major project should have a master bibliography. In mine, I only put works for which I have complete information. So if I don't have the book on hand, but know I have to cite it at some point, I don't have incomplete information in the master list.
I will have another list of citations that aren't complete. The article by what's his name in 1973 that I have to look up later. That will avoid me the frustration of finding that my bibliography has half of its items missing publication years or the names of translators. I know that's one of my weaknesses, so I am addressing it now. Working on bibliography is also a good use of time on days when you need a break from thinking and writing.
A page of bibliography with 15 entries. That means each page in the bibliography might refer to between 300 and 2,000 pages of material. That bibliography stands behind your work, props it up. Of course, in some cases an item will be one you've used for one very limited and specific purpose. In other cases it will be a long book you've studied for years.