Especially frustrating is when I'm starting to build up some momentum which I then loose when I have to interrupt myself to ask "What's your passive Insight/Perception?" Not only does this ruin the narrative momentum, but it tips the players off to something that I either don't want them to notice, or want them to take initiative and discover on their own.
In a brief discussion with Jonathan from The Core Mechanic, I found out that his players have folded cards with their essential stats written on the side facing the DM. For myself, being primarily a laptop DM, I created a spreadsheet for myself on Google Docs:
Not to leave anyone out, I have also created a sheet for DM's that can be printed out. It has entries enough for five characters, and uses the following layout:
Click here for the full-size sheet (1.9 MB .jpg - fits 8.5 x 11 paper)
How do other DM's manage this information? How do they use it to convey details to their players? Would you rather hear "You failed to notice something." or not be told anything on a failed Passive Insight/Perception check? Does it take something away from the players to have a DM tell them when they're hit, rather than continually asking for their defensive stats?