YOU CAN NOT HAVE A MEANINGFUL CAMPAIGN IF STRICT TIME RECORDS ARE NOT KEPT.
Thus, famously, wrote Gary in today's section of the DMG (pg. 37), and I tend to agree, if not with the severity of the statement (the all-caps are his, not mine), then with the general high desirability of keeping "strict time records."
Alas, time is something I've struggled to keep track of, especially in the dungeon, so I was excited when I saw that today's section was on keeping track of time… and disappointed that Gary gives only the smallest bits of advice for keeping time in the campaign and almost no advice for keeping track of time in the dungeon. In fact, Gary spends the vast majority of this section arguing that keeping track of time is important… so let's deal with those arguments first. (Gary says a few other things, but, as with every entry in this series, I'm discussing what I find to be most interesting, not dealing with every last point Gary makes.)
Time in the Campaign
The first reason Gary gives for keeping time is that when the party splits up and one group uses more time than the other group then it becomes possible to encounter weird time-related conundrums; for example, if on Monday group A goes on a week-long journey, returns and kills a dragon on Day 7, game time, and then on Wednesday group B visits the dragon's lair on Day 2, game time, what happens? The DM must realize that group B won't be killing the dragon, as group A has "already" killed the dragon on Day 7. Whether the DM makes sure the dragon isn't at home, leads the encounter away from violent confrontation or just makes sure the dragon is invincible, this is an important point for DMs to keep in mind, especially when running a campaign where different players can play on different days.
Gygax goes on to point out that the loss of time is what makes healing hit points meaningful; otherwise healing full hit points is costless and assumed between each adventure. PCs also spend time away from their bases while adventuring, incurring bills if they rent and risking attack and capture of their homes if they own them. Perhaps even more significant than either of these is the time it takes to craft magic items, which must be uninterrupted and so necessarily cuts into adventuring time. Additionally, though Gary doesn't elaborate, and I wasn't aware of this stricture in AD&D, time is a factor in leveling and training. Keeping track of time also gives an impetus for players to play their PCs' henchmen while their "regular" PCs are otherwise occupied, giving the henchmen character and a chance to level up and possibly set out on their own.
Finally, Gary states that keeping track of time, that is, making time an element of the game, is worthwhile simply because it is the addition of another interesting set of choices to the game. I buy that.
Time in the Dungeon
Keeping track of time in the dungeon is important because the DM must know when to check for wandering monsters, when spells with certain durations cease their effects and when the party must stop for a rest (every 50 minutes and after every strenuous activity). Gary also lays out that a round is one minute and a turn is ten minutes and explains that time records should be kept on a separate sheet of paper.
OK, so that, in my mind, pretty satisfactorily settles the question of the desirability of keeping time records, but my personal question is not "why?" but "how?" especially for inside the dungeon.
I suppose this is actually pretty simple, on paper. As a referee, I just need to figure out the slowest member of the party's movement rate and count out the party's movement on my map as the PCs move through it. In practice, though, I find this really difficult. Maybe it's just me, but all the times I've tried to count spaces and calculate time while providing description of the dungeon to my players, listening to them describe their characters actions, figuring out the immediate consequences of those actions, answering their questions and keeping the greater workings and context of the dungeon in mind… I've ended up giving up on keeping track of time within the first five or ten minutes, real time.
What I have been doing is using Faster Monkey Games' Turn Tracker (they seem to have a new print version here) and advancing a turn whenever it felt like a turn had past, in game. Hardly exact, but also better than nothing. I have a feeling that many in the OSR would approve of that sort of time tracking by "feel" (or find even that too confining), and maybe I just have too strict a definition of "STRICT." On the one hand, using the Turn Tracker has been working for me, so it can't be all that bad; on the other, both for my own satisfaction and to keep the fairness to my players as high as possible (I probably track time by "feel" too quickly or too slowly… or both), I'd like to be more exact. Any advice on this would be appreciated.