Once in 15 years, twice in a decade... Ive given it 3 times in 9 months...
Give plenty of warnings, then I give it. Its time wasting and I only count once the keeper is comfortable.
So if he goes to ground for a save and takes a second to look around before getting up etc, I dont count that.
But when they are composed, on their feet and looking at options, I watch my watch religiously.
As a goalkeeper of many many years many many moons ago, I always played to this rule.
Now - we need to do something about goalkeepers that take 45 seconds to take a goal kick.
No joke.
I have about 3 or 4 in my league alone that take an age to take a goal kick... Most of the time, they're losing.