little useful bit of info showcmd
How to see how long selection (visual) is?
How to see whether you have accidentally entered any numbers which would act as repeat counter for the command?
The little thing I always forget about::set showcmd
In right bottom corner (before ruler) little useful bits about actual state of keyboard input in normal are displayed.
Most useful is of course to now how long visual selection is, which I use often to e.g. count number of characters.
P.S. Documentation says the showcmd setting will be changed if you changed compatible mode. Shouldn't be a problem since no sane person uses compatible mode anyway.