i have it on constantly, and is set to boot to tv at start, so i primarily use it to control my satellite through, works great - only issue is it darkens the picture depending on your kit, because of a bug in the hdmi colour space (make the image clip blacks and whites) - there are workarounds....ie, choose DVI, instead of hdmi (even though you are connected to hdmi) [as that gives correct settings] and then use optical for audio
also, regarding heat/wear - the xb1 is a large console, with a large chassis which is better for heat dissipation, also the PSU is external, in the power brick, which reduces heat compared to units with internal supplies, and thus far haven't had any issue with heat etc, as it was pretty much designed with this ability in mind
i guess you can look at it like its essentially a computer, and we all know we have our computers on a heck of a lot!