Searching for expired patents is a totally valid and surprisingly effective way to find your next product idea.
Rich Goldstein made this point on the Serious Sellers Podcast, noting that the patent system itself creates opportunities. Once a utility patent expires (after 20 years) or a design patent expires (after 15 years), that invention enters the public domain. It becomes fair game for anyone to manufacture and sell. A lot of sellers see a patent number and stop, but the patent could easily be expired.
Goldstein also mentioned a key insight: many people get a patent for a great idea but never actually launch the product. The patent archives are full of these vetted but unmarketed inventions. This means you aren't just looking for previously successful products to remake; you can find brand new opportunities that already have a proven, documented design. This is a powerful form of product development strategy.
Your first step is to use Google Patents. As Rich Goldstein advised, when you see a patent number on a product, always look it up. Don't just assume it's active. You're not just doing defensive research to avoid infringement; you're actively hunting for opportunities.