I agree Arnold. My start at kitbashing first destroyed two pricey kits, so I entered my design with some serious trepidation. Most of these kits are pretty expensive so you have to enter a kitbash with a strong stomach or bank account.
Yeah. By my thinking, "kitbashing" is best practiced using random boxes of mismatched Plasticville parts, at least at first (look under the tables at the train show). This greatly lowers the stakes and makes experimentation and practice much more palatable.
A close relative to kitbashing are the so-called "craftsman kits". These are usually a box of pre-cut raw materials, and they are another "ice breaker".
Arnold's comments point out the fact that when you are buying any kind of kit, you are getting two different things: (a) a box of parts and (b) a carefully-thought-out design for a structure. These are two different things, and for many beginners "b" may be just as challenging as "a". Another way to address this is to scratchbuild a REAL building, working from photos. That is what I did with my gateman's shanty shown above. This lets you concentrate on materials and skills--inheriting the design from the architect of the real structure.