i buy bolts.
i never buy theme or trendy fabrics by the bolt because i just don't go through that much of those types of fabrics.
i typically buy batiks by the bolt and flannel for charity baby quilts.
then i buy numerous prepared for dye (PFD) bolts, i dye all my own blenders and screen print much of my own fabric. i also dye all my backing fabric.
i buy PFD in 44, 60, and 120 width. right now i have 150+ yards of PFD in the house and it will last me till the end of the year.
i get empty bolt boards from the LQS - they are more then happy to give them away.
i have a very large walk in closet in my room so its not a problem for me to store bolts of fabric, batting, fusible webb.
i tend to buy by the bolt for most things because its cheaper.