Speed-Boost WiFi Extenders: When They Help and When They Do Not

It can reduce throughput, particularly when it uses the same wireless connection to receive and retransmit. The effect depends on model, band and conditions.

It can improve WiFi in a weak-coverage area but cannot raise the broadband speed supplied.

Place it where the router signal is strong, use a suitable band and consider Ethernet backhaul if supported.

Not necessarily. Match standard and ports to router and devices; a high theoretical rate cannot overcome a weak source link.