@leader21 Thanks for the feedback. I agree the battery life time depends much on the number of triggers and this way the acceptance depnds much on the usage setting. Like @koffienl pointed out a PIR in the hallway you may have a high frequency of triggers which may finish the battery in a few days/weeks. It may be ok though for a less frequenctly occupied space, e.g. the cellar. To be able to roughly compare battery it is required to count the number of triggers/hits like @koffienl did.
@koffienl Regarding Xiaomi gateway I am also testing this right now which may be a good choice if you use it for several smart home applications as sensors/actors are relatively cheap. My biggest dislike right now is the “chattiness” of the gateway which talks to several hosts on Amazon Cloud and China and produces a lot of traffic.
My advice is to block this traffic which is relatively easy to accomplish if your access router allows for blocking internet access for LAN devices. You may need to open it up again, however, if you need to pair new devices (haven’t tested this yet, however).