EricShapiro

extension DateFormatter {
	/*
		DateFormatters are notoriously slow to create, so it's best to share them. 
		However, they're not thread safe, so this returns one DateFormatter per thread.
	*/
	static var shared : DateFormatter {
		let key = "com.relium.swift.DateFormatter" 
		if let f1 = Thread.current.threadDictionary[key] as? DateFormatter {
			return f1
		}

EricShapiro

Reasons to create UIs in code rather than Storyboards:

Merge conflicts 

Easier to diff revisions and see changes in code

More flexibility to move UI elements on iPad vs iPhone,
portrait vs landscape

Easier theme support