Multiple sources...
( ( Netflix || Amazon || NowTV ) && ( NAS && ( Pi(s) || Roku || Chromecast ) && ( ( Charity Shops && New disc seller ) || ( Charity Shops ) ) ) )
1) General stuff to watch, I stream, or pick up on a whim in a charity shop.
2) Stuff I know I, or one of my family, really like and will likely want to watch again, I keep an eye out for in charity shops.
3) Stuff I need to see at the first available opportunity, I buy new.
If I buy it, I rip it to my NAS, keep the disc (in large CD binder(s)) and sleeves (in shoeboxes) for defence against The Man and stream around the house / copy to a device for trips away.
Same with music ( 'cept with free Spotify/Deezer), similar with books.