Worth considering getting a few - because the the Xiaomi Aqara sensors are inexpensive and accurate. Their only major issue is that they're finicky about which zigbee repeaters they work with.
There's a nice thread by @veeceeoh (who has written/maintained/collected drivers for the Aqara devices), about which zigbee devices work well as repeaters for Xiaomi Aqara, and equally important, which ones do not work. The thread is here;
The thread with drivers for Xiaomi Aqara devices is here:
Edit: The Ikea outlets are $10 apiece. Three placed "strategically" were sufficient to cover my ~2000 sq ft two storey townhouse.
