I have been collecting since the start.. I actually was one of the people to buy a bunch of the first hats that came out... I knew they would be valuable due to the limitation.
Ever since then I usually get them from the store.. I have access to 3 accounts so I use all 3 to get the hats..
I got lucky with the big 16 hat addition (the last one) I got on Graal and 5 minutes later metris and a ton of hats were released.
I just like having all of them to be able to say I have the complete set. It's nice to be able to go through any hat and wear one at any time. I have quite a lot of extra hats too but most are gone due to me selling them at the market.. I stocked up on the new hats and I have plenty to sell.