Oxygen Sensor replacement 2003 X5

Hi guys, i just rolled my 2003 X5 past 100k miles and have been doing some preventative maintenance. Next on my list is replacing the oxygen sensors. The ones on there are still working fine buy the manual recommends replacing them and I'd like to take care of it before they go out. I know the pre cat sensors are the most important to change and usually go out first. However im contemplating on whether i should change the post cat sensors as well. I read these almost never go out. Should i bother with the post cat's? Most the DIY videos i see they only replace the pre cats. Those post cats look like a pain to get to. I'd like a straight up unbiased opinion. Thanks for any advice.