Thoughts on formal skill challenge

I have been ruminating on adding formal skill challenges to our 3.5 game. I am an equal opportunity borrower; I gleefully borrow rules from 4E, earlier editions, other systems, or other folks generously shared house rules. A rule is just a tool for the DM to help run the game. Use the ones that work; delegate those that do not to the garderobe and let the otyugh have them. There is something about the idea that I like. The question for me is: is creating formal skill challenges worth the effort that goes into them? It took me a while to understand what they meant by skill challenges, and how to use them. I suspect I was not the only one based on the amount of chatter on the boards on the topic and the errata and how to files that have been furiously posted after release. Finally after internalizing what was meant the next question was: how is that different from what I do already as DM in the game? I am leaning towards answering my own question with the response of - not much. Example of a simple skill challenge: A character is chasing or being chased. Both the chaser and the chasee have the same movement base. There are rules for resolving this by rolling dice, and if the player does not want to step up and use skills and abilities to resolve this problem then we can use the rule. However, I would much prefer that player take an active role in overcoming this challenge. Tell me how you change this reality? A player might: cast a spell to alter the reality (make themselves faster, opponent slower, stop the opponent outright, etc), tell me how they use their superior strength or endurance to outpace the other, or tell me how they use the environment to their advantage creatively using a skill (strength to push aside brush, escape artist to get through difficult spaces, intimidate or diplomacy to alter a crowd of people, bluff to fool the opponent, the possibilities are nearly endless). I have always viewed the subsections of my adventures as sort of a skill challenge. Yes you fight your way through some of it, but you can use your other tools as well. Usually there are benefits in using a characters various other skills and abilities rather that straight forward hack and cast. So what have they done for me in codifying skill challenges? So far I am thinking not much. I am an experienced DM, so I am usually ready (expecting) for the players to NOT follow the path I set for them and have to improvise. Therefore I am quite accustomed to adjudicating a players creative use of their skills to solve a problem in ways I had not foreseen. Since my track record for predicting what my players will actually do is abysmal at best - what value is there in spending valuable and limited time to 'precisely' define what skills and difficulty levels are required to solve the problem? (I think I am foreshadowing the answer, no?) On the other hand if generous gamers post clever skill challenges that I can borrow and convert with little effort - praise be to Arimal goddess of those who 'borrow' may she bestow her luck on those who enrich my game. My 'skill challenges' are more like a series of balloons and arrows with some logic points (yes go here - no go there; if then else; etc). Sure there are points where I document precisely what is needed to succeed on a certain element, but I do not formalize the entire process. I am not completely done ruminating on this, but so far I am not inclined to spend valuable preparation time in this level of detail.