So I've been thinking about running a game at the office in the spring. And I'm contemplating starting it at 1st level.
I have never run a game starting at 1st level, in any edition, that I can recall. And I'm worried about the wild fragility of 1st level characters, and that 2000 XP is a lot if you're taking regular casualties. You could easily end up having to earn something like 5k XP each before getting any particular character to 2nd level, losing it all over and over again. I don't know that I want to spend that much time running super-low-level dungeons, never mind trying to retain players during massive attrition of PCs.
Reserve XP is, of course, an option, particularly with the interpretation where it isn't spent when you bring in a new character.
But another thought that occurred to me was that we could instead make 1st level more granular. The big difference between 1st and 2nd is that your HP doubles, in expectation. And you'll always gain at least 1 HP. What if, at XP halfway between 1st and 2nd, you gained 1HP? And then when you hit 2nd, you lose that 1 bonus HP but instead gain a rolled hit die?
1HP doesn't sound like much. Even for a fighter it's 20-odd percent on average. And for a 1st-level wizard, it's a 40% increase in HP, on average.
So it's kinda like 1.5th level. And then Arbrethil on discord pointed out that going from 2nd to 3rd is also a really big power bump, between 2nd level spells and a further 50% increase in HP (even without ACKS' fighter damage bonus increase). So maybe we need a 2.5th level too...
(If we did Iron Heroes-style hit dice, where d6 got turned into d4+1 and d8 into d4+2, we could be even more granular - could cut 1st level for fighters into four segments, one with d4+2 HP, then d4+3, d4+4, d4+5, and then finally 2d4+4 at 2nd level)
It also occurs to me that, in light of the big increases in survivability already taking place from 1st to 3rd level, maybe it's actually OK to delay improvements in saves and to-hit until 4th like B/X does. I don't know that continuing to do big jumps in to-hit and saves every couple of levels makes sense after that point, but at the very beginning it almost seems defensible.
But I'll probably chicken out and start them at 2500 or 3000 XP like I usually do.