I have been noticing this of late. Before when I used to pick up an album or two, I used to keep listening to it for days together till the songs got stuck in my head even if it was an average album. I even used to give the terrible ones atleast a dozen listens till I could atleast identify the tracks. But nowadays, even if I feel the album is good, it's tucked away. I dont listen to it sometimes for about a month. A lot of albums I've picked up which I liked but have listened to it just 1,2 or 3 times. I find my mind getting diverted somewhere else and before I know anything the album is over. I go back to listening the older ones that I have where I remember all the songs. Is it that I'm picking too much stuff? My interest in metal sure isn't dwindling. Or is it that I have too many things occupying my mind? Or is this just plain normal?

You'll retrace your steps eventually. Keep buying, and keep having fun. There's a lifetime left to enjoy this shit.

I'd say it's normal. I do that sometimes. I'll forget I haven't heard an album I bought and it'll be stuck in my collection untouched for a few months. That's usually b/c I buy my music buy the dozen and lose track. Also, sometimes I’ll have music playing in the background and lose my concentration on it b/c I’m doing something else. That doesn’t mean it’s bad, it just means I have a one track mind at times.