What makes an enduring movie franchise? For generations, studios and filmmakers have tried to crack that formula for a property that will keep the audience coming back time and again, with varying results. While plenty of franchises have kept churning them out, more often than not this has resulted in slews of repetitive sequels which gradually burn out whatever charm the material once had, more often than not losing the audience's interest in so doing.
However, there are those occasional, special franchises which manage to recover from disappointing entries, dust themselves down, and come back to full strength - or sometimes even stronger than before. That's like catching lightning in a bottle as far as the film industry is concerned.
Here are 15 such franchises, listed from shortest to longest-running, and roughly sorted within their number categories from worst to best (all very scientific, ahem). To keep the focus on lengthier franchises, I haven't listed any that run shorter than 7 entries - and a few of them have further instalments due in the very near future.
It's often said that quality and quantity cannot go hand in hand; do these movie franchises prove that notion wrong? They might not all be Oscar material, but damned if they're not entertaining enough to keep us coming back for more.