I've been collecting and playing with Transformers since 1984. They're just damn fun toys to play with and I love the lore. I had people tell me I was too old for Transformers as early as 1985 - I didn't listen to them then, I sure as hell wouldn't pay any attention to such comments now!
I have a room in my house that isn't just a collection room, it's my play room. I still do the whole fantasy play thing - story, voices, sound effects etc.

Just yesterday I was playing around with WFC Optimus Prime, Drift, my PCC Commanders, moofie Scattorshot, Cybertron Scattorshot, Animated Cliffjumper, Animated Blitzwing, Animated Dirge, Animated Thundercracker and Crossovers Battle Droid/Tank.

You can read about it later on the Toy Story thread.
I think I'd stop collecting Transformers if I ever stopped playing with them. Which thankfully I never have. Although I have stopped playing with some other toy lines, which I will be putting up for sale soon.