Random Roll: DMG, p. 12

 Page 12 of the Advanced Dungeons & Dragons Dungeon Masters Guide includes a short section of "Starting Level of Experience for Player Characters," which I found interesting. Gary Gygax begins by stating the obvious:

As a general rule the greatest thrill for any neophyte player will be the first adventure, when he or she doesn't have any real idea of what is happening, how powerful any encountered monster is, or what rewards will be gained from the adventure.

True words have not been written! I think, on some level, we're all hoping that, one day, we might re-experience this "greatest thrill." I further suspect that this hope plays a big role in why we continue to try out – and buy – new RPGs: "Maybe this game will remind me of what it was like when I first ventured into the Caves of Chaos when I was 10 years old."

This assumes survival, and you should gear your dungeon to accommodate 1st level players. If your campaign has a mixture of experienced and inexperienced players, you should probably arrange for the two groups to adventure separately, possibly in separate dungeons, at first. 

I'm unsure if Gygax's use of the phrase "1st level players" is intentional or merely another example of the conflation between "player" and "player character" that can be found throughout the DMG. 

Allow novice players to learn for themselves, and give experienced players tougher situations to face, for they already understand most of what is happening – quite unlike true 1st level adventurers of the would-be sort, were such persons actually to exist. 

Combined with what Gygax wrote in the sentence immediately before this, I'm struck by how different my own early experiences were. In those days, it was not uncommon for neophyte players to join an already established campaign, bringing their newly-minted 1st-level characters to a party consisting of higher-level ones. I don't think this was anyone's preference, mind you, but it was a fairly standard practice and one we simply accepted as "the way of things." After all, if your 1st-level fighter survived even a single session adventuring with the higher-level party, he wouldn't be 1st level any longer.

If you have an existing campaign, with the majority of the players already above 1st level, it might be better to allow the few newcomers to begin at 2nd level or even 3rd or 4th in order to give them a survival chance when the group sets off for some lower dungeon level. I do not personally favor granting unearned experience level(s) except in circumstances such as just mentioned, for it tends to rob the new player of the real enjoyment he or she would normally feel upon actually gaining experience levels by dint of cleverness, risk, and hard fighting.

I completely agree with Gygax here. In the past, I have occasionally allowed an already experienced player to join a campaign with a higher-level character, but that's no longer my practice. Whenever a new player has joined my House of Worms Empire of the Petal Throne campaign, his character started at 1st level, even though the other characters were more experienced. I'm not sure I can justify this practice of mine beyond saying that I simply prefer that all characters earn their levels in the same fashion. After nearly seven years of continual play, it's worked out quite well and I see no reason to change it.

It has been called to my attention that new players will sometimes become bored and discouraged with the struggle to advance in level of experience, for they do not have any actual comprehension of what it is like to be a powerful character of high level. In a well planned and well judged campaign, this is not too likely to happen, for the superior DM will have enough treasure to whet the appetite of players, while keeping them hungry still, and always after that carrot just ahead. And one player's growing ennui can often be dissipated by rivalry, i.e. he or she fails to go on an adventure, and those who did play not only had an exciting time but brought back a rich haul as well.

My qualms about the phrase "the superior DM" to the contrary, Gygax speaks truly here – or at least it comports with my own experience as a referee over the years. I'd only add that it's not only treasure that can serve to whet the appetite of players. Just as often knowledge and other rewards are every bit as motivating. (Gygax's reference to rivalry between players is something I haven't experienced since I was a kid, but I concede it may well serve as a motivator in some groups.)

Thus, in my opinion, a challenging campaign and careful refereeing should obviate the need for immediate bestowals of levels of experience to maintain interest in the game. However, whatever the circumstances, if some problem such as this exists, it has been further suggested that allowing relatively new players to participate in a modular campaign game (assuring new players of characters of high level) would often whet their appetites for continued play at lower level, for they can then grasp what it will be like should they actually succeed in attaining proficiency on their own by working up their original characters and gaining high levels of experience.

By "modular campaign" does Gygax mean the use of adventure modules? If so, this would seem to suggest that he saw the purpose of these pre-made adventures to be, at least in part, to serve as a "training ground" for players in what it would be like to play at various levels. If that's right, I don't believe I've ever seen this sentiment expressed anywhere else before. Even if that's not what Gygax meant, it's nevertheless an intriguing idea and one I'm not sure I'd ever considered before. If nothing else, it possibly sheds some light on why TSR often published modules whose suggested levels were much higher than anything typically achieved in most campaigns.