Correction, 8/26/14, 9:55 a.m. EST: An earlier version of this story incorrectly stated the amount of space Sheppard, Mullin, Richter & Hampton will occupy in its new Washington, D.C., office location. The firm will occupy 58,000 square feet. The story has been revised accordingly. We regret the error.

Law firms are trading down in square footage per attorney when they take out new leases, and increasingly are looking for flexible, more economical spaces in line with the corporate clients they serve, commercial real estate experts say.