Hard Hats Curbside Trash Replace Hard Hats Often Hard hat shells need to be replaced every 2-5 years depending on the environment they’re used in, and they need to be replaced immediately if they are struck by anything. Inner suspension needs to be replaced every 12 months. Refer to the manufacturer for explicit safety recommendations. Ways to Reuse Turn Your Hard Hat Into a Planter You can repurpose old or unwanted hard hats as outdoor hanging planters. Get inspiration from these examples on Pinterest. Did You Know? The History of the Hard Hat After World War I, Edward W. Bullard created the “hard boiled hat,” made of steamed canvas, shellac and black paint. These hats were optional for miners and other laborers until the construction of Hoover Dam in 1931 and the Golden Gate Bridge in 1933, the first two projects where hard hats were required.