I torque everything to spec when it comes to wheels, brakes and stuff like that. Just makes me feel better about it being on properly!
Torque wrench not expensive, so you may as well:
http://www.amazon.co.uk/Silverline-...8&qid=1447159053&sr=8-1&keywords=toque+wrench
I would recommend a nice long breaker bar for getting it off as well, but then that's dependent on your bike. I never needed one with my Hornet, always came off easy with the torque wrench, but with my new bike I needed a breaker bar + wanted one anyway, nice to have in the toolkit