Speaking as someone with a 5.1 system they haven't set up: Getting the rear speakers' cables installed into your walls is expensive, and requires you own your

Speaking as someone with a 5.1 system they haven't set up: Getting the rear speakers' cables installed into your walls is expensive, and requires you own your home. Getting a room large enough you can get several guests between the speakers without some of them ending up much closer to the speakers than others is even moreso.