Recommended. Don;t even have to be on same circuit. Wi-fi booster version works a treat too. Best of both worlds. Use TPLink 500s - get the plug throughs
Used to have the TPLINK ones which were great for xbox downstairs and PC upstairs. Nó use for them at present.
As for the adapters, just buy a 2 pack and if one is spare either keep it or bung it on ebay. When I was buying them it was about a quarter of the price extra for the 2nd. So you'll make a good 50-75% on selling one.