I was recently told that the previous owners of our house used casing instead of the trim throughout the house. What is the difference between window casing and trim? Are there are got-yas that I need to be aware of because one was used and not the other?
Trim is a general term, often used to describe all types of molding and millwork.
Casing is a type of molding, typically used to trim the perimeter of windows and doors. Casing is typically less wide (tall?), but thicker than base molding.
Base molding (or baseboard) is a type of molding, which is applied where the wall and floor meet.
Crown molding (or crowns) is a type of molding, which is applied where the wall and ceiling meet.
I think what the person was saying, was that the previous owner used casing in place of base molding.
You can always add a decorative strip to enhance the thickness of the casing if it bothers you that much but if it looks good, don't worry about it and leave it. It's for whatever look that pleases you. It's just different words they use in construction for certain decorative accents. It's like getting gels instead of a regular manicure.