It is possible that your neighbors’ Wi-Fi signals could interfere with yours and this is especially the case if you have signals above, below, left and right of your apartment.  This is more the case with the 2.4 GHz band. It’s something to consider if you’re looking at a budget router.  You can often get around this by repositioning your router, changing to the 5 GHz frequency or changing the channel if your router allows you to do this.