Preface: so, nowadays I run official modules mainly..I might spend 2-3 casual hours prepping battle maps and have an encounter or two/quest board prepped if they decide to go somewhere else. I’m a very visual dm..I do a ton of handouts and battlemaps for every situation(even social). I will probably listen to an actual play from people I like, while working, during the week before session for that chapter. Question! How much prep do you do prior to a session?

I will prep for (apparently) years before a new campaign.

I do so because if I do it properly my total prep time is less than an hour for a single session as a result.

Average prep time is really about six months for a campaign, and then 60 to 90 minutes through a week leading up to a session. Since I don't use anything that is published (setting, adventures), the hardest ting is when II see a thing that is published and want to take ideas from it. Because localizing a published adventure can take 8 to 10 hours easy.

that said, most of my prep is reviewing where they were, what they were doing, and referencing my outlines. THe rest of it is very much on the fly, because my entire game is player driven. I just have to be able to describe it clearly.

Yep, I kind of figure where they are at that moment. Possible choices where they might go based on 2-3 paths. Have some random battlemaps ready if they go a different direction. A tavern or manor setting where they can rest/gather their wits. Battlemaps if unused are modular-I can upgrade the encounter as needed. 

If I prep for 30 minutes for a single session, that's a lot. And most of that time is spent finding the right music, NPC pics, and writing up my recap narration. 

I used to prep like 10-12 hours each week, easy. I run homebrew intrigue campaigns, and my previous one had a lot of complicated villain motives and machinations, so most of my prepping was devoted to ensuring my lore was consistent and analyzing political repercussions. Once I started burning myself out, and after I realized I DM better on the fly, I stopped prepping except for dungeon mapping and puzzles. 

For my current campaign, I do my prepping in spurts. I'll spend like an hour or so every few weeks thinking up potential encounters and challenges to throw the party's way. I also thought up a long list of quest hooks before I started the campaign, and the entire setting is based loosely on a novel I was writing years ago, so I have an instinctive handle on the universe and background events. But for the most part? I wing it.

Yah I kind of fear too little prep..but some of this is unfamiliarity with different adventures at different levels. New advenuture I brainstorm during the week and start serious prep 3  hours out(this while maybe recruiting/onboarding a new player)..30 minutes out have the maps ready. Sweating a bit. I am not a no prep dm.

It's hard to say. Unless I'm setting up a big encounter or a lot of potential small ones, or writing up a significant amount of info for the players, it's all done in bits and pieces in random moments of downtime, then possibly recorded in my phone's notes. I'm actually planned unusually far out at the moment, because I just had to write up an infodump, and then my brain started to fill in all the implications of the players following up on it.

But then, I can keep a lot of state in my head, and make a lot of things up on the fly (as long as I don't have to name anything :). I don't suggest my methods for anyone else.

i spend about an hour on combat encounters that is the easiest part., Mapping  is dependant on how detailed i want it to be for dungeons i prefer old school like maps  and for outdoor or city i prefer are more colorful maps  so those always take longer, background and rp content  anywhere from 3 to 5 hours.  However, there are times however when creatively i am in the zone so to speak and content  comes much easier on those occasions i end up with the session i am working on and something i might i will use down the road.  needless to say one note is my friend.

I dunno? I don't really track it. In general terms I do probably three or four hours of thinking over the course of the week, but that's more general D&D prep than prepping for the next session. I do a LOT of improv, so much of what I'm doing is finding new random tables that I can use to spark inspiration at the table. Another thing I do is read the books looking for general ideas. If I'm really thinking about it I might put in about half an hour of work that's dedicated towards a specific session, but not a lot more.

For example, I was doing some yard work earlier today and started thinking about how I want to handle something a recurring villain will probably be doing two or three sessions from now. I didn't write it down, but I came up with an idea for what they would be sending and what the goal would be.

I find running online takes more prep because the maps/visuals play a bigger factor than in person. In person, you can create encounters and maps on the fly that appear prepped and ready to go but online, having to find tokens, put stuff on maps or create nicer looking maps (you can use a hand drawn battle map online and I've done so but it isn't as good as an in person hand drawn map just due to the drawing tools) takes time.

In addition, if I am running a published module, I will read/skim the entire module before running it because there are often plot elements that are very poorly integrated or which don't make much sense without some earlier foreshadowing. (For example, in Out of the Abyss, there are a number of encounters that depend on a timing earthquake or landslide. I find these far too unlikely an occurrence unless I foreshadow it by making the earth shaking and moving a relatively common occurrence. So I had several earthquakes with minor effects before and after the events that required an earthquake as a trigger so that they didn't see as out of place.) Similarly, the motivations and plot drivers of some of the NPCs can be better understood in context by the players if I can throw in some foreshadowing. A comment by a bad guy, a rumor in a bar, an overheard conversation with some random piece of apparently useless information that can later tie in to what the party learns to make the overall plot and NPC make more sense. This kind of stuff requires reading the module to figure out what is actually going on (e.g. Like in Rime of the Frost Maiden, there is a very good chance that the players could end the main quest 2/3 of the way through leaving them no real reason to go to the Reghed glacier UNLESS the DM has been building up the secondary quest into a main quest option that the characters need to follow up on even if they succeed in defeating Auril during their first encounter).

Anyway, I use published modules for online play since the maps/tokens/dynamic lighting is already done saving me a huge amount of time. With that out of the way, prep for a session usually just involves reviewing the material I think the party is likely to encounter which takes 30-60 minutes in most cases.

Quote from David42 >>

I find running online takes more prep because the maps/visuals play a bigger factor than in person. In person, you can create encounters and maps on the fly that appear prepped and ready to go but online, having to find tokens, put stuff on maps or create nicer looking maps (you can use a hand drawn battle map online and I've done so but it isn't as good as an in person hand drawn map just due to the drawing tools) takes time.

 I get around this by just using dry erase maps and snapping pics with my phone to a maps channel on Discord a couple times per round. I tried the digital maps thing and found it too time-consuming to stick with. I respect the online DMs who aren't as lazy as I am, lol.