I get the kits and then I have extra bits that I can use for other bikes. It comes in handy quite a bit and if I don't use it I can give it to friends or use it on their bikes. However I am a person who likes a well to over stocked parts bin so I am always nicely set up to build a bike or repair one of my own or have stuff to sell in case I need a quick couple bucks.

They make the Jagwire kits in a 1x set up so if you don't need so much it comes with less (a bit more than 1 foot but again doesn't hurt to have extra)

You could also do as dedhed said and just go to your local shop and get a foot of housing.