Jan 2020 puts me at 20 years collecting DVDs and now Blu-ray. I had a collection of about 600 VHS which I started in 1987 and I believe I bought my last VHS in 1999 which I gave to my adult children. I never bought any HD and 4K.

Been about 20 years. Not sure which was my first DVD, I think the first one I bought was Disturbing Behavior, but also got a few with those mail-in rebates when you bought a DVD player, as well. I believe one was Sphere.

I started with Beta and VHS in the mid 70s. Beta was better than VHS, but VHS won. I never got into Laserdiscs, but I remember having over 400 VHS tapes when DVD started. I got my first DVD player in 1999. My company sent me to Canada to one of our other offices for a few days, but before I left, I set up the player and told my wife to go out and buy a couple movies. She bought "The Matrix" and "Godzilla". The first DVD I watched was The Matrix.

Side note: The Matrix Reloaded was the 1000th one we bought. I remember because at the time we were buying about 4 to 7 DVD every week. We were at 996 at that time and I picked The Matrix Reloaded off the shelf and gave it to my wife to hold. I then proceeded to pull 3 others from the shelf and made her wait until I purchased them. Then she bought the Matrix Reloaded. So, 1 and 1000 were the first 2 Matrix movies. With so many 4K and 3Ds in our collection now, we have replaced many, many movies with newer versions. Some as many as 6 or 7 times. We are now forced to buy the 3D and 4K versions separately, for the most part, a few come in the same case. The US has almost completely quit producing 3D discs, so we get most of them from the UK.

Sorry to ramble, but once I got started, I couldn't stop.

20 years? Those are Rookie numbers! 

First two DVDs on 31st July 1998, "The Crow" and "Dune", both imported from the USA and played on my Creative Encore PC-DVD DXR2

Also at slightly over 20 years! Bought my first disc (Small Soldiers) at the end of 1998 or very early 1999.

Sure, I’d happily do another 20 years..\

I'm coming up on 22 years for collecting discs. Jan 9, 1998 was my first DVD purchase (Spawn) from Suncoast Video.
I had been loosely collecting VHS for many years before that. My very first purchase was the VHS of Alien back in the mid 80s, back when they were rental only and not for general sale. I paid $80 for that VHS...and I still have it!

Got my first DVD  in Oct 1997 ..  and at about $25.00 each or more ..  My first title ? 
Woodstock  the 225 min version with all  the extra's  etc ..
But when the 2014 BD release of Woodstock was shown to me in which I replaced the #1 dvd in my library.
It absolutely blew away  the older version. the old version was very blurry  and muted colours., The new version has superior bright colours and hardly ANY GRAIN ..

Great topic...

First recorded purchase according to my records is April 1997:  Batman Returns and The Long Kiss Goodnight.