If I buy a lot of yardage, like 4+, I will tear off what i need, as Scissor Queen suggested. Planning your cuts so they wind up on the exact grain of the fabric is not as important in quilting as in garment or drapery construction. Think about fussy cutting pieces. They are not going to be on the grain. The quilting will stablize the fabric if it's a bit off. Somewhere I read that the 'fabric print trumps all' and this is how I proceed. Drives me crazy if the pattern goes off wonky on quilt. I match up the selvedges, but if the pattern is printed off square, I cut to match the print.
As far as the half yard cuts, I can see where a beginner would find this much more manageable, but as you gain experience, you should be able to work with longer cuts.