Proper Table(s) Layout

I have created a couple of Dbs which the table structure seemed to simply
fall into place, it was just logical in my head.

That said, I am working on a new db and for some reason I am doubting myself
and wanted a second opinion.

The db is basically a contract db to input all the info, and there is a lot
of info, for each contract. Where I am 'lost' is the fact that the contracts
are broken into categories: clients, components,engineering, warantee... For
all of the components (with the exception of clients) there are a number of
fields but only 1 entry per contract.

Basically my question is, should I be rolling out one huge table with all of
the data or should I be creating a project table and then multiple category
table with a 1-to-1 relationship? My gut is telling me to go with a single
table, but at the same time I have never needed to create such a big table
and it feels wrong!

Thank you for your enlightenment on the subject.

QB