In between adventures, one of my Game of Taps players (I think it was Doug) asked if it would be possible to get some new level 0 characters so he'd be ready "when these guys die." Yes, Doug, an enthusiastic yes you can. Every session or so, the guys would add a new level 0 or two (with a firm cap on the number of characters each player could have set at 4). Some folks preferred to run with fewer characters, some with more. Either way, I reasoned that the GoT crew was quickly depopulating the Keep on Kickassistan and something needed to be done; at this rate, they were turning out to be more deadly than the Caves of Chaos themselves!
I thought about what sort of wages your average dude in the world of Kickassistan is likely to expect and figured that a silver piece is about right for a daily wage (I think I got this idea from somewhere fairly "authoritative," but that could all be BS; also, this is in normal game coin, not Metal Gods of Ur-Hadad's suilver standard) and thus, following the logic, 10 gp would be about 100 days' worth of labor and that became my benchmark figure. Effectively, this 10 gp retainer is a "death benefit" paid to the family of the newly-recruited level 0 character in case he never returns from the "adventure" (read: path to pain and perdition) that he's being hired for. This 10 gp is not a deposit, but rather a payment made to the family preemptively, just in case. I warned the players that they could be depopulating the Keep and the surrounding area and as a result, they now are pretty careful about hiring on a bunch of 0s.
Which brings us to the problem that I thought I was experiencing. Every session or so, folks would be rolling up fresh level 0s to replace the 0s now in fresh graves, and paying 10 gp or 10 sp per head to do so. Was this too many 0s? Were my players sending too many foolhardy bakers and barbers, costermongers and coachmen to an early demise? Was I making the game too easy by offering the players reinforcements at the low, low price of 10 coins? Would the game(s) get completely fucked and never be playable as a result of me bungling the "replacement PCs" issue? Okay, that last one might take it too far but it does highlight the issue: by allowing my players ready access to new level 0s, was I making the game too easy?
The answer to all of these questions is "no." Here's why. The precise number of level 0s being introduced to the game was the precise number of level 0s that the players wanted to have. They paid the price that I established and often these 0s took a single hit before expiring on the floor in a pool of their own blood. This system does create the possibility of "accidental characters" (like the mule minder mentioned above who haphazardly makes it to level 1), but those characters have to go through their own individual funnel as much as a fresh batch of four 0s does. Furthermore, the game was being made too easy by the presence of these 10 gp disposable heroes, but rather exactly as easy as the players had wanted. The players got their way, got their extra level 0s and if that made things easier than I had intended, then, as the Judge, I can dial back the amount of experience attained.
In DCC, characters don't split one big pool of xp that gets divvied up to each character from a lump sum total. Rather, each character is given an amount of xp depending on how challenging the encounter was. A relatively easy encounter will garner 1 xp, whereas a normal encounter will garner 2 and a complete walk in the park nets not a single point of experience. In my game, half of the players at the table have to lose a character in order for me to even consider awarding 3 experience from a single encounter and never have I yet deemed it appropriate to award four (and don't think it'll be happening any time soon). Each additional character added to this mix reduces the difficulty and thereby reduces the overall experience award for all of the characters involved, thus slowing down everyone's rate of advancement with the result of increasing survivability. Less is being risked, therefore less is being gained.
For the most part, this post has been an explanation of the thought process I went through last night when I started to think my DCC games might be getting too easy (I know that Metal Gods players are cringing right now as I suggest that campaign might be too easy) because of the number of level 0s that I was continuing to allow into the game. All in all, I've come out the other side of the thought experiment completely unworried because (a) the players are choosing to add more 0s, (b) they're paying for them, and (c) the easiness if being paid for in lower xp awards per fight. This whole post might seem like too much hubub over not enough of a problem, but as someone who really enjoys it when the game hits that sweet spot of just the right difficulty and challenge, I'm really pleased with how it's working out so far.