The poll has brought out several related, but distinct, issues.
1. The question asked was, what is your 'first try reg
recovery method' (FTRRM). I read that as, how do I locate a primary second stage that has - for some reason - come out of my mouth? And, the offered poll options seem fairly inclusive. But, my FTRRM will depend on the length of my primary hose. If I am diving a short (e.g. 32-36" primary hose) my FTRRM is option 2 (side lean and sweep). If I am diving a 7' primary, my FTRRM is to trace the hose from behind my head, down my right side (essentially option 7, 'some other method').
2. Several responses have actually addressed the broader 'lost reg
procedure', which involves both a) assuring continuity of gas supply, and b) recovery of the reg as well as . Like many posters, my FIRST response in the case of a 'lost (primary) reg' is to go immediately to my (bungeed necklace) alternate. That assures the gas supply continuity. THEN I work to recover my primary second stage. This sequence is NOT the commonly taught procedure in most agencies. I think it should be, for a number of reasons that are best discussed separately. In fact, I had a discussion with PADI about this earlier this year after an instructor mistakenly stated that PADI 'does not allow' instructors to teach a recovery procedure that involves going to the alternate first, then recovering the primary second stage. The statement was incorrect, of course. But, I wanted to be sure I hadn't missed something in some standards revisions somewhere.
The PADI training person I spoke with did indicate that she personally didn't believe going to the alternate was necessary, since a competent primary 2nd stage recovery would quickly restore the continuity of the air supply. But, that is a matter of individual preference, from my perspective.
3. The issue of WHY a diver needs a 'lost reg procedure' in the first place is interesting and is related to, but not the same as, the procedure itself. I guess I have been fortunate, that I have never had my primary second stage kicked / pulled out of my mouth by another diver. But, I have also not yet been in a situation where I encountered an OOA diver, so that (having my reg pulled out of my mouth) could still happen in the future. I have lost my primary reg a couple of times, due to my own (really silly) mistakes.