Day One, or at least close enough to spit. I'm not sure *how* I first heard of them, my brother had got the UK comic, and the iron-on T-shirt transfer, but I can't tell you exactly when it became a *THING* for me.
I have strong memories of Birthdays and Christmas being dominated by star Wars figures, until the Christmas of 1985, when I received Grapple, Bumblebee, Cliffjumper, Brawn and Gears, and my birthday in '86 when I got Optimus Prime and Megatron, and then Christmas '86 with The Arielbots and Stunticons... so I fell for them in that time frame, and was certainly reading the comics at Dinobot Hunt, because I remember cutting out the "order form" for the weekly books from the Snarl issue of it.
I also remember going to see The Movie at Cine City in Manchester, which had Labyrinth on it's other screen, and my Brother trying to convince me to see that instead.
2) When was the point you realized you were not leaving?
I *did* leave, I'd stopped the UK comic when I started getting the US one, and the last toys I got were the Classic Pretenders, and they just weren't as good as they were, and I'd really got into other things, like looking at boys and being confused, or american comics, like JLI. I glanced at TF's occasionally, vague eye contact with it through Beast Wars, although I never owned one of those toys, because why animals?
Beast machines really spoke to me for some unknown reason, it was awful, but in an Image Comics sort of way, which appealed to me at the time, but beyond that vague awareness I was out for good.
I remember seeing issue one of the Dreamwave comics in Forbidden Planet, and it not connecting with me, it followed the Cartoons, which wasn't the REAL, UK Comics continuuity, which was totaly bullshit, and the art seemed clunky and weird, and not in a good way.
I went to Transmasters UK, on a lark really, paid for Eugenesis, which arrived in the post a few weeks later, as James had sold all the copies he had to hand, and I bought a G1 blaster, Eject, Rewind and Ramhorn, but just met SO many assholes in there, being looked down on because I called "Car Robots" the wrong name, or didn't know what a Masterforce Bracelet was, it was kinda a full stop situation, I had my older comics, and some toys, and that was that.
The next toy I bought was Armada Hotshot, because I had Toys R Us vouchers, and needed to use them that day, and he was just awful, and that was it for me and Transformers.
Then came the day I saw Classics Bumblebee in Woolworths (Staines branch) and HE suddenly fixed everything. I still love that toy, and have a lot of versions of it, and he lead to me getting that entire first wave of classics, Grimlock almost took me right out of it again, and I picked up the trades of the 2 war within series, and again, I sort of fell out, I picked up the occasional Classics toy but the (by now IDW) comics, and their 3 human leads, left me cold. the Bay movie was OK, but didn't make me care, but what did, and I suppose this is the short answer, meeting fellow fans, who WEREN'T assholes, mainly online, that was great, THAT was what got me back in properly, and still keeps me around until this day.
Well, that and DC pulling New 52 bollocks and freeing up comics money for me just in time for the comics to get good again... that helped too!
For the lapsed fan, it's Last Stand Of The Wreckers. LSTOW is The Hobbit for modern Transformers.
For a New fan, volume one of MTMTE, sort of by default, it's where the modern era really starts, with Death Of Optimus Prime acting as the first line, and then it all goes from there.
Usually if I'm acting as a pusher, I'll give someone MTMTE and RID volume 1 to them, because that's where is starts.
Prime and now RID2015 are also great places to start for new fans. Appealing character designs and fun characters are a fantastic first taste.
For "new" people, I gift them MTMTE and RID, for reasons I state above, usually I've already had them watch B*G and Firefly, which are great populist scif-fi, and I get good pick-up from them, 75% of people stay with us
For regular comics fans, comparing the current IDW books to the JLI books of the 80's/90's works well, it's an odd little shorthand for CHARACTER.
I've started meeting a lot of Comedy people, stand-ups and improvisors, and telling them that Arrested Development, 30 Rock, Parks And Rec, Spaced and so on, are in the cultural shorthand of Transformers now, it almost moves mountains to get them in to the comics.
MTMTE and RID exploding in the (small) way they have. They've brought new sorts of fans in, women and queer and weirdos and arty people, they've splashed new life and new colour into, what was always sort of an assholey fandom, and it makes everything so much better. Windblade showed up, and the positive response pushing the negative down to almost sub-audible levels sort of proves how we've matured and evolved as a fandom.
Last Stand Of The Wreckers though, it's our goddam Hobbit!
Classics Bumblebee. HE IS FUCKING ADORABLE!
Tailgate. Tailgate is a highlight. She's the character find of the 2010's. The chubby lil' baby!