You can go to the Falls on your own and there is no safety requirement to use a guide. They're available if you need or want them (ie; maybe to take pictures of you group) but we've never used them on our three trips to the Falls.
The Falls aren't hard at all to traverse if your in reasonable health and shape.
If you are traveling with small kids I was told to definitely use a guide. We are going on our honeymoon so I am sure that my new husband will want to be all macho and not use a guide hehe. I want to use one for the pictures and hopefully some insight on what we are seeing on the way up. We booked a tour thru Peat Taylor. It is $30 and he takes you to the Falls, a beach and shopping it's about a 4 hour excursion. I am not sure if the guy driving us there is also going to go up with us or not. We will see!
great choice KarenB. Peat is great. Getting back to Caren's question, yes you can take a cab on your own to the falls, just make sure that the cab you get is a bonded, licensed cab, they are clearly marked, there are lots of gypsy cab drivers in Jamacia who will literally "take you for a ride". Negotiate your round-trip fare and return time in advance at the pier, that way you will have a guaranteed ride back to the ship. You can climb the falls on your own, you don't have to be a part of the climbing chain if you don't want to, just get in line.
I've done it both ways; a guide is not required. Note: Peat Taylor is great, but he doesn't provide the guide at the falls.
The falls aren't trivial, so if you are a bit concerned a few dollars for a guide may be worth it. It is definitely "do-able" on your own though if you have good balance, a keen eye, and are a bit in shape. On the trip where we had a guide, one of the athletic men in our group fell on some slippery rocks and had a horrible bruise from just below his shoulder blade to the top of his hip. Another athletic friend of my slipped and bent his finger back 90 degrees when he slipped in a hole. The take home from this is, either way you need to be careful! Interestingly enough, of the 20+ people that I know that have climbed it, no woman has been hurt. Guess they're a bit more cautious than us gungho men :-)
Well, I unfortunately, am one of the few women that got hurt climbing the falls. We had a guide and were fortunate enough to be in a small group - only 7 of us. I climbed the falls just fine - on the more difficult right side of the falls as well. It was after we reached the top and I let my guard down - I slipped on the REALLY, REALLY, slippery rocks at the top in the not so fast moving water. I had a bruise from my hip down to my knee - pretty sore too! Moral of the story - be very, very careful from the moment you start up the falls until you are back on dry land.
We climbed it and loved it, we took a cab on our own, then paid the guide to take us up( and about 15 others) .
Would I do it on my own,? Yes, I'd just follow a group. Wear good water shoes, NOT sandals.