(in case you hadn't noticed I like to ask a lot of questions)

I've seen this advice in a few different posts. I recently seen this advice on Twitter for Sage Advice. However, I feel, on the face of it, that's too simple, too subjective. But I do worry about over preparing for my party.

What is 'over preparation'? And wouldn't it depend on the kind of adventure you're trying to run?

Thanks, in advance! :-D

You either over prepare or under prepare. If you are great at improving an entire session then you can under prepare. If you aren't, then you should over prepare. 

Whatever doesn't get used can go back into the bag for later. The PCs will never know the blacksmith was potentially at every town. They just know he lives in the town where they finally needed one. 

So I don't see it as over preparing more than I see it as getting a head start for later. 

Also I like weaving plot points together and allowing anything to happen, so being over prepared is a good thing I believe. 

Over-preparation may happen for both published adventurers and for homebrew ones. The concept is that you may be too meticulous in preparing your campaign (NPCs, side quests, encounters....) in a way that the player will play just a small portion of it.

Yes, of course the whole thing is subjective. My advice is just prepare the frame of the campaign, the general structure. Often, improvising is also fun to see how the player reacts.

My experiences/opinion here.

Over preparation happens when I put a bunch of things together that my players are never going to see, let alone care about. If I've spent hours detailing things, characters and/or places and nothing happens with them or the PCs blow past/through them. I've clearly over prepared. I eased back my prep time and work a long time ago, including 0 prep and full improv which went okay. 

Now if I put a little bit of work in to figuring out how I'm going to start the session things flow pretty well. I recently picked up the book the Lazy Dungeon Master (http://slyflourish.com/lazydm/) and have been trying out the ideas in it. Which actually leads to a little more prep than I've done previously, but I think it's helping my current game.

The easist way to not over-prepare is to know exactly what the players will do. That's not all that possible unless you run a very firm railroad game, which tends not to be as fun for most folks.

From a minimalist and agile perspective I try to have a solid idea of what the players think they will do by asking them directly. First at the end of a session, and then again a few days before the next one. That way I can get a sense of their scattershot of ideas and prep a few related encounters (be they social, combat, etc.). That also gives me a few ideas on locations they may visit so I can tailor the encounters to make sense in their locations. 

After that, planning for the known, I look at where the PC's currently are, where they said they are going, and what's happening in my sandbox of a world around that. This let's me make an extra encounter/location or two as wildcards if the players run off the path they indicated. They can run headlong into one of the regional encounters I've created (your wandering monster table is your friend).

The other controlling factor for how much I prep is how long we are going to play. If it's a weeknight that's just four hours of content. If it's a weekend, eight. So weeknight games take about half the prep.

You do kinda have to just play some with each gathering of players to get a sense of how they use their time. Efficient parties need more prep. Parties that like to socialize and carouse need less in terms of raw encounter numbers, but more in terms of encounter depth. It's a sliding scale too of course ;)

If I manage to cover the targeted encounters (that players said they seek), and regional encounters (my backup fun), and I still have time left? I'm going to do whatever makes me happy as a DM to peper the world with fun. Even if it's at risk of not being seen. The more work of that nature I do, the better my improv. I still try to keep it close to where the PC's are, but at that point I'm not prepping for them, I'm designing for pleasure.

I wouldn't worry too much about it. Just evaluate the couple of dangers that can arise from over-preparing and if they are not occurring then you are fine.

Such as: You are burning yourself out by putting too much work into the prep session and it is sucking the fun out of it for you or taking time from other prep you need to do.

Or: You end up railroading the players too much because you desire them to experience the content you have worked on -- especially if they are not enjoying it.

Great feedback and I really appreciate at. :-D

Right now I'm writing a homespun/sandboxy campaign. And I'm mostly creating it on the fly. This is not to say in an improv style. This is say the 'next' chapter is created at or near the end of the 'current' chapter. So, far I've crafted the chapters to end like a cliff hanger, a big ole "To Be Continued..."

When I'm writing the 'next' chapter I think about all the things the party could do, all the people they could meet, all the encounters they might engage with. Because of my setting (Forgotten Realms, circa 1372 DR), I have a wealth of information from which to pull, glean, borrow, use, etc. So far this has helped me in prep-time because I can focus on the overarching theme, and main quest of the campaign. Again, so far, so good. However, in our 'current' chapter, it was a rewrite of an existing, system-agnostic adventure, and I definitely recognized my over-preparing when defining some of the NPCs. I finally realized those NPCs wouldn't factor into what I had planned; I could play them purely off-the-cuff.

However I also feel, the more I prepare an NPC the easier I'll be able to play them, like a character in a play. I'm not good an improv (thinking about taking some classes BTW) so if I can do the deep dive for my NPCs I'll feel more prepared, I'll be able to provide a richer experience for my party. Again, so far, so good.

And, as for duration, I'm not writing chapters to fit into any time frame. However, I do try to keep each gaming session to around 4 hours; if I had to guess we're getting about 3 hours of actual D&D game play.

:-D I feel like I'm rambling now, so I'll stop...