When I discovered the discount online shops with quilt shop quality---I started buying for stash. I often bought 2-3 yards. Fabric.com has a $3.99 a yard sale a couple of times a year with free shipping on $35 or more. That is when I bought.
ALSO--Thousands Of Bolts and a few times Connecting Threads on the clearance fabrics. Once and awhile I would buy more if it was patriotic as I make lots of quilts for Quilts Of Valor. I once bought 10 yards of a small flag fabric and still have about half left.
You might want to consider a budget per month you can spend on fabric. Then you would know exactly what you can or cannot buy.