LINDA HAYSLETT, 45, is the founder of LH.Designs and has worked for clients such as Sandra Oh and Charlize Theron. “I carry a measuring tape in my purse. At a flea market, I noticed items that were perfect for a project. I shared photos with my client and measured them on the spot. Another client said that since arming herself with a measuring tape, she’s staved off impulse purchases. The numbers don’t lie!” —Niamh Rowe