This depends on how deep you plan on getting into the subject, I have been active in cartography for ~40 years, and absolutely serious about design since the mid 1980's. As someone professionally trained in architectural design and building layout, I would advise that you most definitely use existing and proven examples for inspiration. Specifically: historically and culturally-relevant examples for whatever design you are considering. I do this frequently and unapologetically, as do all designers: we build upon what has been proven to work. For modern design we try "be original" and make improvements, but greatness is obtained by "standing upon the shoulders of giants". This is not a weakness and does not make us less creative, we must simply understand that we must learn from those who came before us to avoid wasting time that could be spent on our true potential.
Historic examples will show how living spaces were arranged and divided apart from working spaces. If you really want to get serious, I recommend diving into historical research of everyday life of people within the cultures for the designs you are considering, (I am watching a documentary on the Middle-Ages/Medieval art as I write this). I typically play relevant documentaries or inspirational audiobooks in the background and have multiple historical reference images while I draw.
For my "Cthulhu/gaslight" drawings I have several books of Victorian-Era house designs. These show how homes were planned before the common availability of electricity and even pressurized running water (in rural locations). These designs also illustrate cultural norms that we no longer consider, hence the importance of historical references.
There is a great deal more I could suggest, but I think the point I intend to make is: don't disregard other sources or other someone else's design. Looking at how people live and work is how professionals know how to arrange things. If you use a source from history, make sure to give it credit (I do when I remember to) and don't plagiarize other's work, but there is nothing wrong with learning and gaining inspiration from those who have come before you.