During my last session one of my players was trying to pick between two powers to use against a foe and, in the process of debating, asked me what he needed to hit. Without thinking I blurted out the number. I was caught off-guard; normally I don’t share those things, and I was pretty upset about it (more with me for responding without thinking than with him for asking).
I was upset because I like to keep the players guessing. I don’t like to let them know exactly what they need to succeed; if they figure it out in play then that’s fine, but otherwise I enjoy keeping them in the dark, using terms like “you just missed!” or “that shot went really wild” to indicate how close they are to hitting. Similarly, I keep my NPC modifiers secret, in spite of a “no fudging” policy (I go back and forth on “showing the roll”).
By contrast, I usually let my players keep damage tallies for NPCs (not the total health, just how much damage they’ve done). This flies in the face of my “keep them in the dark” policy, as they can observe how much damage opponents take before falling (would they really remember if they weren’t keeping totals?), but I prefer the ease on my bookkeeping more than the integrity of keeping them in the dark.
So how about you? Do you worry about mechanical transparency? Do you keep your players in the dark at all times or do you simply hold off transparency until, for example, the initial encounter is over? Or are you the type of GM that gives out mechanical information at the outset?
Have you ever taken mechanical obfuscation to extremes? Have you, for example, refused to tell players how much damage their characters have taken (restricting info to “you took a solid hit” or “you don’t think you’ll survive another blow”)? Have you kept modifiers hidden (i.e. “your magic sword gives off a minor blue glow”)?