سوال for longtime ER fans?

I myself have been a پرستار for a long time but, my problem is the fact that it's inherited XD Technically I've watched ER from the very beginning, except for the beginning of the first before I was um, BORN XD So needless to say during most of the older seasons (till about season 9) didn't really understand what was going on, but because it had always been a part of my life I loved it anyways. As I got older my devotion just grew and sadly when it ended last سال probably was about the time I was mentally able to become a true پرستار (I was 15) so missing it very much I decided to buy all of the season that are on DVD and watch through them. Now to me real question, after watching through the DVDs I noticed that the "previously on" segments aren't included on the DVDs until about season 10, is that because they just decided not to include them on the earlier seasons, یا did they not exist before then? I could swear I always remember those segments being part of the دکھائیں but maybe I am remembering wrong. Could someone please help me out with this. Please and Thank you!!!