I use a 2015 Retina MBP (13inch) and have been experiencing wifi disconnections since I have upgraded to El Capitan. I am now using 10.11.5 and the problem remains. I am experiencing wifi dropouts on this computer only. My wife uses an old 2011 MacBook Air with El Capitan 10.11.5 and has no disconnections. My other devices iPhone + iPad Mini are also on the same wifi network and do not experience any problem. I have tried many of the usual suggestions such as: throw previous wifi preferences to trash, created new wifi profile/location with google dos, changed MTU to 1453 and disabling Apple Wifi Direct Network (awdl0) and nothing seemed to do the trick. I cannot seem to find a proper answer anywhere but have seen many people experiencing the same problem. Any help would be greatly appreciated.
side note: the only annoying "fix" is to manually renew my DHCP lease or turn off / on my wifi which takes longer to get back online. If i do nothing, it will get back online after a longer period (less than 1min).