The #1 problm of WiFi networks (well before the speed of data transfers)? Merely, the network range. There is always a corner of the office or of the house that is not reachable (or nearly not reachable) with your WiFi-enabled laptop: in the master’s room upstairs when the router is installed in the office downstairs, for example.
Solution #1: buy a range extender or a repeater. But this is usually very expensive (several hundred dollars).
Solution #2: reconfigure a 60-80$ router to transform it into a nice cheap WiFi repeater (a device that takes the WiFi signal, amplifies it, and re-broadcast it at full power to extend the available range).
I was thinking about this when I found the two interesting explanations describing how to install a new “DD-WRT” firmware on a consumer wireless network router (like a Linksys WRT54GL) and to configure it as a repeater:
And it works even with a WiFi network that was correctly configured for security.