It shouldn't affect. Just make sure you give access to the right devices on your router.
Few things you could do:
- Change the Wi-Fi password, if it's still the default or some common password
- Filter the devices by MAC address
- Disable SSID broadcasting
These last two could make it a bit inconvenient if you have someone coming over, because they need to enter the name of your network and you need to add their MAC addresses to the filtering list.
If you have a Cisco router, they usually have this feature called Wireless Protected Setup (WPS). By activating it, it will allow someone to, in a short time, join your network with the password and automatically add their MAC address to the filtering list.
Also, you can try the Avast Home Network Security scan, to check vulnerabilities on your router.
But stay tuned, we're working on SecureMe for iOS, which will also provide this scan functionality.
You can read more about here:
https://blog.avast.com/2015/03/02/new-avast-secureme-app-protects-ios-and-android-users-from-wi-fi-hacking/