You'll want to update your home inventory when you acquire a new item or items that significantly change the overall valuation of your home's contents. You don't need to update it every time you shop, but significant purchases warrant an update. If it's been a while since the last update and you've made a lot of smaller purchases, it's also worth updating your home inventory list to ensure it accurately reflects your belongings. Make the updates a lot easier for yourself by keeping your purchase receipts where you can easily find them, which will also make tax season much less stressful.