Roughly speaking...

From 1984-1987/88 my brother and I had the second or third largest collection amongst our peers. Then the kids with larger collections sold them (I got Soundwave and Gnaw for $5 each!) and so our collection became the largest. After the Marvel Comics were cancelled our collecting declined. By 1992 my brother had stopped collecting altogether and I only picked up a few figures. The G2 years were definitely the slowest for me in terms of TF collecting.

It picked right back up again when Beast Wars came out and I went nuts collecting. Then the bloody 2002 drought came... I wanted to keep buying but there were hardly any new toys to buy! My wallet breathed a sigh of relief, but the collector in me sure was frustrated. I even bought RiD Optimus Prime despite the fact that I got Super Fire Convoy 2 years before just cos I had nothing else to buy! (sad huh?) My purchasing would've peaked in 2003-04 when I was buying a lot of repaints (although most of them I gave to my gf atm who's also a TF fan - so they never went into my collection). Shortly after that I wound down and tried to become more discerning with what I bought - and that's pretty much where I am now.

In terms of volume, I'd also say that I've been buying a lot more since 2007 just because there's a lot more of stuff out there to buy, what with all these lines running simultaneously (movie, Animated, Universe etc.).