I use a Davy knot to tie on the fly - or a Double Davy for large flies - and while the knot works just fine it somehow didn't seem like enough knot for the rings. I guess that's kind of silly if I trust it for the fly, but adding two more of them seemed kinda scary. Being terribly lazy I normally don't even use a tippet; I just keep using the leader until it gets too short or too fat , which is dumb and I need to change that. Back when I did change tippets I used the Orvis tippet knot which I remember as being kind of a pain to tie.