Go outside right now and check to see how your stairs are attached to your deck! I just inspected a set that was 18 feet long and was only attached with a couple nails into railing posts!
In the graphic above, notice the lovely 4 by 6 bolted to the stair stringers and then to the deck joist.... How about those lovely straps! Finally, with a really long staircase why not put in two posts in the middle to reduce strain at the top and give you some assurance that heaven can wait!
PS: We home inspectors have some pretty bad nightmares, e.g. Your only daughter just got married and you're having the reception in your back yard. Mom is nervous, dad is very proud. The whole wedding party lines up for a photo on the lovely, long staircase of your deck. Bride is on the top stair, best man, in his powder blue tux is on the bottom stair. He was a star lineman in high school and has had too much champagne and gained a little extra weight in the intervening years. The perfect shot is finally lined up but the best man suddenly decides to jog up the stairs past everyone else and give the bride a back-bending kiss...but he doesn't make it and the honeymooners must cope with plaster casts (awkward!).
In some cases these hangers are all that's needed. Click on image for link.
Here's the real stairway to heaven (or at least one of them) in Westmoreland State Park.