Wifi encryption itself is pretty secure. The WPS feature on many routers though can be easily cracked and it gives them you wifi password. You want to make sure this feature is disabled.
Still someone has to be very close to hack your wifi and most people are lazy. It is a business that would have much more concerns.
Even if someone would get into your network on wifi your machines firewall has pretty good default protection. There really is not much incentive to hack a home users pc, lots of effort and not likely any money to be made. Mostlyit is kids who are trying to hack their neighbors wifi not to attack the machines but just to get unfiltered internet access that their parents have prevented.