If your beauty budget is high enough, you could also use a product match service such as threecustom.com. These specialise in recreating shades that have now been discontinued. All you need to do is send them a sample; you can also get them to create a color based on a photo. It's admittedly not a cheap option, but ideal if it's a shade rather than a product that you love.

There's almost certainly stocks of your favorite discontinued product around: you just need to know where to find them. Enterprising companies have realised that there's a market for selling discontinued products. Look for websites like discontinuedbeauty.com or buymebeauty.com, which specialise in selling discontinued and hard-to-find beauty products.