There are scores of new papers proposing or discussing new Beyond the Standard Model physics theories every week (at arXiv and elsewhere) and unless you have an infinite amount of time you can't read them all in depth. What "triggers and litmus tests" do you rely upon to identify, either papers that look promising on one hand, or papers that aren't worth your time to pursue, on the other? For example, I pretty much immediately ignore any paper that relies on tachyons to explain something. On the other hand, I pretty much automatically follow up on any paper that claims to show an experimental result with a deviation from the SM or GR of 2.5 sigma or more (unless it calculates a look elsewhere effect of less than 2 sigma). I also ignore pretty much all papers about how a newly proposed experiment would discover something if it were ever conducted (which really deserves its own category, for what it is worth).