Back in January, both my father-in-law and I each bought 01515's during a run to our local Lowes. We've had them installed and running at our houses since that time (his in the mountains, mine here in the desert) and things were running nicely until this summer. Back in late June, my sensor's hygrometer took a dump and would register 1% humidity and negative dew points on any day where humidity was near 15%. The only way to wake it out of its 1% slumber was to power-cycle both the external and internal units.
My problems were rectified by the nice people at Acurite's customer service, who sent out a new sensor and the issue has been corrected (current humidity is 13% - yay !). But a month ago, my FIL called to say that his rain gauge was reading too high. So on my subsequent trips to the mountains, I've been troubleshooting the his 5-in-1 sensor as well. I've done everything to the 5-in-1 but completely recalibrate his rain sensor - including making some drastic adjustments to the sensor's sensitivity with little improvement (as in adjusting it by -24%). During my next trip up, I'll completely recalibrate the rain gauge to see if things improve, but I wonder why we both have had issues with our 5-in-1 sensors.
(Disclosure: My 5-in-1 hygrometer definitely failed since installation; my FIL's rain gauge may never have worked right, so it may have come from the factory that way.)