I will say that really knowing your options helps. I'm in a b/x osr and upon reading the rules for that particular one, I realized I could wear leather armor and carry a short bow. Yeah, I couldn't cast spells while holding the short bow but since I only had one spell at first level, I would use that spell first, which was enlarge/reduce and then switch to the bow. Three out of the four of us did get knocked out at level 1 but we still made it through.
I saw that somebody mentioned taking an elf in B/X but my DM does not allow them a humans because he says they're more powerful and really he's against bills that differ in power. He's not wrong that the added hit points, weapon use with one hand while being able to cast spells, and a few Marshall actions would help, and that only starting with read magic wouldn't make much of a difference, but the worst saving throws and experience progression probably would have messed me up if I was an elf.
I'm talking to a DM now about joining a 2nd game, 2E, and I saw that same person mentioned taking a specialist in to me, and although I like evokers in 5e, I can't imagine having such a low percentage of knowing spells us at my school and just not being able to take useful spells. Like what if I roll poorly on all the defensive spells? Plus the fact that I wouldn't have access to two schools of magic, but I'm not as worried about that.