I found a shampoo that had been sitting in my bathroom cabinet for almost two years! The kicker is, the bottle was still full, but had been opened. I had used the shampoo a couple of times and then stopped for what reason I couldn't recall.
Additionally I had some hair serums and oils that were older than I could remember. Same with a moisturizer and hair grease. Seeing how old these products were I got curious about whether or not I should still be using them on my relaxed hair or if I should toss them.
From my research I found some surprising things about how long hair care products last and how you can tell when it's time to toss them. Check out this infographic to see what I learned.