Not sure this be useful, but...

[dmrev]

What about CFTimeInterval and CACurrentMediaTime() instead of NSDate?

private static var executionTimeByName = [String: CFTimeInterval]()
...
if let lastExecutedTime = executionTimeByName[name] {
            let elapsed = CACurrentMediaTime() - lastExecutedTime
            shouldExecute = elapsed > limit
}
...

[soffes]

I like NSDate more.