Oftentimes, I have friends that ask me to help them fix their wireless networks. On more than one occasion, they only have one or two computers in their home, so there really is no reason for the network to be slow due to saturation. What I often discover is that they either are a victim of interference in the 2.4GHz wireless spectrum, or they have a low quality/damaged wireless adapter. With laptops, it is usually more of an issue of a low quality adapter because all the major players put cheap network cards in their machines. Other times, especially with desktops and USB adapters, they are simply damaged, which usually involve a bent USB connector.

If they end up needing a new wireless adapter, it is a case of buying the cheapest one available, or buying the next wireless generation (in this case 802.11ac) for future compatibility. Usually, I recommend that they spend the extra money so that they will get the best speeds when they upgrade their router at some point. Some of them even decide to bite the bullet and upgrade their router at the same time, once they realize the potential speed increase over 802.11n devices. Once they have all 802.11ac compatible devices, and realize how much smoother everything is able to run, there is no going back.