That is the question!
Well I can't stress enough that you SHOULD NOT be in a hurry to join SAG. Sure there are great benefits but unless you are equipped (meaning your resume is strong and solid) you are not going to be a fierce competitor amongst the other SAG actors therefore you could be doing yourself a disservice by joining before you have the experience to back you up!
I have met many casting directors in the past few months and they all have said do not join SAG until you are a "must join". Meaning until you HAVE TO JOIN!
There is a lot of non-sag projects out here for us to build our resume with and once you go SAG you can not work on NON-SAG projects anymore....and that sucks for you if you can't successfully give the other SAG actors a run for their money!
I hear right now that a lot of SAG Actors are going SAG Financial Core (FI-CORE/FPNM(Fee Paying Non Member)) meaning you are still paying your SAG dues (partial dues to the union I believe) but you don't get the benefits of being SAG HOWEVER you get the chance to work on both SAG and NON-SAG projects! The actors are doing this because they are having a hard time finding paying jobs for SAG Actors since there is so much non-union work out there. FI-CORE is just the gray area...I think its best to be either SAG or NON-SAG!
It's a personal choice, but for me...I'm saving SAG for when I know that I am ready to stomp with the big dogs and get these major blockbuster roles!
There's no need to be in a hurry to possibly put yourself out of work before you can even get started working consistently!
A friend just told me she met a guy who's a SAG Actor and he bartends and he's having a tough time finding work...look the industry is already very competitive and unpredictable....don't make things harder by trying to move too fast!
Just my 2 cents :-)