Yeah I wouldn't do this personally, though its not very frequent, I ended up with a defective motherboard when I got all my parts. Also prices change as time passes so you may end up missing out.
Rofl I'm not that stupid. I'm buying the cheaper parts like the case and some of the fans first. I'm buying ram motherboard and processor all at once right before I build it. Also, already bought the 980ti and I tested it in my current comp to make sure it worked.