Bulk buying ammo — is the per-round savings worth the upfront cost?

I'm trying to decide whether to keep buying ammo a box at a time or commit to a 1000-round case when I see a decent price. The math obviously favors the case but that's a chunk of money to drop at once, and I worry about storage and just having that much cash sitting in a closet instead of my savings. For those who buy in bulk, do you actually shoot enough to justify it or do you just like the peace of mind?