My issues started back at the time that I was collecting VHS tapes - and I was able to fill a bookcase with somewhere north of 300 of them, double-rowed on each shelf. The rest began multiplying across all the other shelves and bookcases in the living room.
Then the laserdiscs and DVDs arrived and all the rest of the shelves quickly filled up.
The numbers got to be enough for me to box and retire just about the entire VHS collection to the attic. I sold or gave away almost all the VHS movies I had which had been duplicated either on laserdisc or DVD - unless there was something specifically different that was not available. (The '97 Star Wars SE's, the TV cut of Star Trek TMP, a few other odds and ends)
Then the DVD situation got out of hand, and I had to divide out some subsections - like TV shows, concerts, sports, documentaries. At this point I was having serious trouble finding space for any books on my bookshelves.
Then between the Blu-rays and the SD DVDs, the situation continued to blossom, until I finally broke down and bought two Ikea custom cabinets. At this point, I have managed to contain the collection within the cabinets, with separate sections for Blu-ray and SD DVD in alphabetical order, and then separate sections for TV, music, plays, sports, documentaries, science fiction, animation, franchises (Star Trek, Star Wars, Indiana Jones, James Bond, Matrix, Harry Potter, Lord of the Rings, etc), and a couple of shelves for the bigger box sets. I have also separated out the Criterion Blus and SDs on the top shelf of each side of one of the cabinets, for the obvious reason.
Even with this, I have only been able to keep things under wraps by retiring DVD editions of movies that have been supplanted by Blu-rays. In most cases, I have kept the DVDs boxed in the attic, as the Blus either did not carry over all the features of the DVD, or had other differences. The nice part of this arrangement is that I've been able to find shelf space for all of my books again!