That doesn't make sense to me. Wouldn't more things break if you only updated them every six months and had to retest the whole system rather than the parts that changed as you went along.
I found that upgrading Ubuntu/Debian to the next release always screwed everything up as basically all the packages changed. Heck fedora couldn't even update to the next release until fed up came out.
2015 release used kernel 3.18, some drivers were lagging[1] so I went back to arch. But the latest 2016.03 release is now on 4.4, I'm about to try. I saw many people saying they were happy using nixos on twitter. It's a paradigm shift that require a good deal of RTFM. Felt like the first time I used linux somehow.
[1] my wifi chip took minutes to initialize due to proprietary blob issues.
But I like Arch too. I just switched away from it because I got tired of things breaking if I wasn't religiously upgrading.