Jeff wants to know why his internet slows down at night. Leo says that he ends up sharing bandwidth with his neighborhood and if it's slowing down in the evening, it's because everyone is on Netflix. He also has to factor in Wi-Fi congestion. Jeff could bypass the Wi-Fi router and plug directly into the modem and see if it speeds up. If it does, then he'll know it's Wi-Fi congestion. If not, then he'll know it's his because of heavy use in the neighborhood.
Router age can also be a factor. If he's had the router for a few years, it's probably worn out. Getting a new dual band router could do wonders toward speeding it up. Especially if he uses the 5 GHz band, which isn't used as much. Leo likes the ASUS C3200. It's not cheap, but worth it.