Home Network - hard drive?
I know this has been asked before, but I’m on my phone and can’t be arsed to search! 
Is anyone using multiple computers on a home wireless network with a single external drive serving those laptops? Music files/Traktor/iTunes collections only.
What’s the read time like? Is there much of a delay when loading/analysing tracks in Traktor?
Worth doing?
It can work. Generally, you can get performance plenty good enough for music. But, it depends a good bit on the setup.
Apart from different APs interfering with each other (APs will try to talk to un-associated devices just in case, like your neighbor’s devies for example). And, if you have a lot of devices, you’ll only get that bandwidth for little slivers of time when the AP is actually talking to your computer. WiFi gives the same “time slices” to your computer as it would to wifi lights, printers, and all the other junk a lot of houses have.
So, even if your stuff is fairly simple (just your laptop, phone, the NAS, and a smart TV or game system), you’ll only be able to use it about 1/4 of the time. That gets cluttered and annoying quick.
So, it really depends on a lot of details.
Wired would be fine.
Generally, though, it’s probably a better idea to keep the files locally and sync them where you need them via dropbox, spideroak, syncthing, nextcloud, or a dozen other things designed to do exactly that. You also get multiple copies, which eliminates a single point of failure. And if you use one that runs off a cloud (aka, other people’s servers), you get off-site copies for no marginal cost.