How inaccurate is your inventory and how do you deal with it?

Our full counts are usually off by somewhere around 5 to 8 percent, and I honestly can't tell whether that's normal-small-business messy or genuinely terrible. We know where it comes from. Receiving gets entered late, transfers don't always get logged and returns sometimes make it back to a shelf before they make it back into the records. We've added spot checks and double counts. They help, but the same drift is there again by the next full count. What variance are other people living with? At what point did you accept that the manual process had hit its ceiling?