@HardDriveFail Good day, 

Thank you for your valuable feedback. 

May I know how did you find RE305 reboot, can you help check the if Power Led flash at that moment?

• Please make sure the  environment  temperature is not too high for RE, put it to somewhere well ventilated.

To locate the problem, can you help confirm some details here:

1. The Model of router and your network topology, for example: router Archer C7 ---- RE (AP mode)--PC 
2. How many devices are connected to range extender,  may I know the model of your wireless/ wired client including its operating system. 
3. Is there any high traffic network activities, like File download, video streaming etc. when this issue happens?  
4. If possible, after RE reboots, please login to tp-link web page, save the system log and send the log file to us, thank you. ( keep RE plugged in when collecting log)

How to log into the web management page of the range extender (new logo)?
https://www.tp-link.com/support/faq/1398/

Thank you very much.